This Tagalong Sheet Cake recipe will satisfy your Girl Scout Tagalong Cookie cravings anytime of the year! This recipe is made with a shortbread cookie crust & a moist & decadent chocolate cake that is topped off with chocolate ganache, a creamy peanut butter frosting, and peanut butter chocolate cookies. This cake is delicious!
This recipe is made with store bought cake mix to make your life a little bit easier, but if store bought cake mixes are not your jam you can use my chocolate sheet cake recipe. Also, if you wanted to make cupcakes, a bundt cake, or a 2 layered cake out of this recipe please see my FAQs section below for all the details on baking temperatures and times for those.
WHAT YOU NEED TO MAKE THIS CHOCOLATE SHORTBREAD COOKIE SHEET CAKE
- Chocolate Cake Box Mix: Any brand of chocolate cake box mix will do.
- Shortbread Cookies: I like using Lorna Doone shortbread cookies, but you may use a different kind of shortbread cookie. You’ll need at least 10 ounces.
- Pure Vanilla Extract: Gives flavor! I get my favorite pure vanilla extract from Costco.
- Butter: Melted. I recommend using unsalted butter.
- Buttermilk: Make sure you bring the milk to room temperature. Avoid lower fat or nonfat milks. Milk with fat will give you the best flavor and add moisture to the cake. If you don’t have buttermilk, you can make a DIY sour milk substitute. Add 2 teaspoons of white vinegar or lemon juice to a liquid measuring cup. Then add enough whole milk to the same measuring cup until it reaches 1 cup. (In a pinch, lower fat or nondairy milks work for this soured milk, but the cake won’t taste as moist or rich.) Stir it around and let sit for 5 minutes. The homemade “buttermilk” will be somewhat curdled and ready to use in the recipe.
- Sour Cream: Makes cakes moist! Make sure sour cream is at room temperature. I would suggest removing from the fridge an hour or so ahead of time.
- Avocado Oil: Since cocoa powder is a particularly drying ingredient this cake needs oil for suitable moisture. You can also use vegetable oil, canola oil or melted coconut oil.
- Unsweetened Cocoa Powder: Use natural cocoa powder in the cake, not dutch-process.
- Eggs: Make sure you bring the eggs to room temperature so they can effortlessly mix into the batter without over mixing.
- Tagalong Girl Scout Cookies (Optional): For decorating the top of the cake. You can also use any peanut butter chocolate cookies if you can’t get your hands on the Girl Scout Tagalong Cookies.
WHAT INGREDIENTS YOU NEED TO MAKE PEANUT BUTTER BUTTERCREAM
- Butter: I recommend using unsalted butter because you are able to control the amount of salt you want especially when making the frosting. Be sure to bring the butter to room temperature. I always take mine out a couple hours before I want to bake. It must be soft enough so your finger leaves a dent when pressing it. If you forgot to take your butter out to come out to room temperature you can also zap it in the microwave for about 20 seconds. Do not melt the butter completely.
- Peanut Butter: Use smooth or creamy not crunchy peanut butter.
- Pure Vanilla Extract: Gives flavor! I get my favorite pure vanilla extract from Costco.
- Heavy Cream: You can also use whole milk if you do not have heavy cream on hand.
- Powdered Sugar: Also called confectioners sugar. PS- you do not need to sift it!
WHAT INGREDIENTS YOU NEED TO MAKE CHOCOLATE GANACHE
- Heavy Cream
- Chocolate Chips: I love using Guittard milk chocolate chips.
WHAT SUPPLIES YOU NEED
- 9×13 Inch Pan: Metal, glass or disposable pan is fine. Either will do. I love using Fat Daddio pans.
- Offset Icing Spatula: You can find one on Amazon or you can use the back of a spoon.
- Pipping Bags: I get mine from Amazon.
- Pipping Tips: 1M pipping tip. I get mine from Michaels.
- Food Processor
HOW TO MAKE A CHOCOLATE SHORTBREAD SHEET CAKE
Preheat the oven to 325°F. Generously grease a 9×13 inch cake pan.
In a food processor, blend up the shortbread cookies until a fine powder forms. Add in the melted butter and stir until combined. Press the crust in the prepared baking pan and press firmly in an even layer with the bottom of a cup. Pre-baking is not required.
In a large bowl, whisk together the buttermilk, sour cream, eggs, oil, and vanilla until combined.
Mix in the unsweetened cocoa powder and cake box mix.
Whisk until throughly combined.
Pour the batter into the prepared pan. Bake for 27-30 minutes or until a toothpick inserted in the center comes out clean. Baking times vary, so keep an eye on yours.
Note: The cooled cake may slightly sink in the center. Cocoa powder is simply not as structurally strong as all-purpose flour and can’t hold up to all the moisture necessary to make a moist tasting chocolate cake.
Remove from the oven and allow the cake to cool in the pan. Cool completely before decorating. As the cake is cooling, make the chocolate ganache and peanut butter buttercream.
Tip: I like placing my cakes covered in the refrigerator or freezer while I make my frostings and/or toppings. I do this so that when I spread the frosting on the cold cake, the cake doesn’t pull away and I have no issues with crumbs in the frosting.
HOW TO MAKE PEANUT BUTTER BUTTERCREAM
Using a hand-held mixer or stand mixer fitted with a paddle or whisk attachment, beat the butter on medium speed until light and fluffy, about 2 minutes. Add the peanut butter, vanilla extract, heavy cream, and salt with the mixer running on low. Slowly add the powdered sugar. Increase to high speed and beat for 3 full minutes. You can add more powdered sugar if frosting is too thin, more cream if the frosting is too thick, or a little more of salt if the frosting is too sweet.
Makes about 4 cups of frosting.
HOW TO MAKE CHOCOLATE GANACHE
Place chocolate chips and heavy cream in a microwave-safe bowl and microwave for 30 seconds.
Stir well, and then return to microwave and heat in 15-second increments, stirring well in between, until chocolate is completely melted and smooth. Set aside.
HOW TO DECORATE THE CAKE
Evenly spread the peanut butter buttercream over the top of the cake using an icing spatula. I used about 2 cups of frosting. Place the cake in the freezer for 5 minutes. I like doing this so that when you pour the warm chocolate over the frosting it will set quicker.
Next, evenly spread the chocolate ganache over the frosting using an icing spatula. Place the cake in the freezer again for another 5 minutes.
Using a pipping bag filled with the peanut butter buttercream and a 1M pipping tip, pipe the design (see below) evenly all the way around the pan.
Optional: You can also chop up some Tagalong cookies (or any other peanut butter chocolate cookies) and sprinkle them evenly over the top of the cake.
Slice and serve. Cover leftovers tightly and store in the refrigerator for up to 5 days.
TIPS FOR MAKING THIS RECIPE
- Do not over-mix the batter as you risk over-developing the gluten leading to a tough, dry, and dense cake.
- All refrigerated items should be at room temperature so the batter mixes together easily and evenly.
- Make sure to allow the cake to cool before you add the buttercream.
- Make sure the butter is room temperature before you cream it, as cold butter will lead to lumpy buttercream.
- The longer you chill the cake, the better the buttercream will stick to the cake layers.
FREQUENTLY ASKED QUESTIONS
Can I make this cake in advance?
Yes! You can make the cake, the chocolate ganache, and peanut butter buttercream frosting a few days ahead of time and keep them tightly wrapped in the fridge, then assemble them when you’re ready. You will need to pull out your buttercream from the refrigerator a few hours before you’d like to decorate to bring it back to a spreadable consistency. I would suggest once the buttercream has softened whip it up in your mixer before adding it to your pipping bags to decorate. You will also need to zap the chocolate ganache in the microwave for about 15 to 30 seconds. You can also make the entire cake in advance, wrap and place it in the fridge for up to 5 days.
Can I make the chocolate ganache ahead of time?
Yep! You can store in the refrigerator for about a week. Just zap in the microwave for about 15 seconds or so to get it to a spreadable consistency.
Can I make this with store bought chocolate sauce?
Absolutely!
What other toppings can I put on the cake besides Girl Scout Tagalong Cookies?
You can put any type of peanut butter cookie, Reeses Peanut Butter Cups, Reeses Peanut Butter Chips, Kit Kat, Snickers, or Twix candy would be a go swap out.
Can I turn this recipe into a 2 layer cake?
Yes! Grease two 8 or 9 inch round cake pans (which ever size you have on hand), line with parchment paper rounds, then grease the parchment paper. Parchment paper helps the cakes seamlessly release from the pans. Divide the cookie base and batter evenly between the pans. Bake at 325°F for about 27 to 30 minutes—keep a close eye on the cakes and check for doneness with a toothpick. Assemble the cake with a layer of peanut butter buttercream and chocolate ganache. Frost the outside of the cake with the peanut butter buttercream, you can do a chocolate ganache drip and top off with Girl Scout Tagalong Cookies.
Can I turn this recipe into a bundt cake?
Yes! Grease your bundt pan with. Bake at 325°F for about 25 to 35 minutes—keep a close eye on the cake and check for doneness with a toothpick. To decorate frost the bundt cake with the peanut butter buttercream and drizzle on the chocolate ganache. You can decorate the sides by placing the Girl Scout Tagalong Cookies around the cake.
Can I turn this recipe into cupcakes?
Yes! Using a cupcake pan fill cupcake liners 2/3 full. I love using this baking scoop for my regular sized cupcakes and this baking scoop and mini cupcake liners for my mini cupcakes. Bake at 350°F for about 14 to 19 minutes. Yields about 22 regular sized cupcakes. I would decorate by filling the cupcakes with chocolate ganache and topping the cupcakes with the peanut butter buttercream, and a Tagalong cookie on top!
Can I make this with store bought frosting?
Yes! You can use any vanilla store bought frosting. I would suggest using 2 to 4 containers of the store bought frosting. For every 16 ounce container of frosting add 1/4 cup of peanut butter. Proceed to Step 8 on directions on how to decorate the cake.
I don’t like cake box mix, can I use a homemade sheet cake recipe?
Yes! You can use my chocolate sheet cake recipe.
Do I have to decorate it they way you did?
Of course not! If you think the way I designed this cake is too hard or not to your liking then be my guest to recreate your own design. You do you boo!
How do I store leftover frosting?
Buttercream frosting can be stored in the refrigerator for at least seven days. Just be sure that the container is tightly sealed and that you keep the frosting far from pungent foods like seafood since the smells can transfer. You can also freeze buttercream frosting for up to 3 months in an airtight container or freezer bag. The day before you’re ready to use it, let it thaw in the refrigerator overnight, then bring it to room temperature before re-whipping again. This is helpful if you’re making buttercream months in advance, or you have leftover frosting you’d like to use later on.
How do I store cake leftovers?
Cover and store leftover cake at room temperature for up to 3 days or refrigerate for up to 5 days. You can also freeze frosted cake or unfrosted cake can be frozen up to 2-3 months. Make sure to throughly wrap with plastic wrap and aluminum foil. Thaw overnight in the refrigerator and bring to room temperature before decorating/serving.
Make sure you post your photos on Instagram and tag me in them so I can see your creations from my blog #eazypeazylemonsqueezee
Tagalong Cookie Sheet Cake
- April 4, 2024
- 12
- 4 hr
- Count the memories not the calories! Cals/Serving
- Print this
Ingredients
- Chocolate Shortbread Cookie Cake:
- Shortbread cookies (10 ounces), pulsed to a powder in a food processor
- 4 tablespoons unsalted butter, melted
- 3/4 cup buttermilk, at room temperature
- 2/3 cup sour cream, at room temperature
- 3 eggs, at room temperature
- 1/3 cup oil (avocado oil, vegetable oil, canola oil or melted coconut oil)
- 1 Tablespoon pure vanilla extract
- 1/2 cup unsweetened natural cocoa powder
- 1 box chocolate cake mix
- Chocolate Ganache:
- 1 cup chocolate chips
- 1/2 cup heavy cream
- Peanut Butter Buttercream:
- 1 & 1/2 cups (3 sticks) unsalted butter, at room temperature
- 1 & 1/2 cup creamy peanut butter
- 1 tbsp vanilla
- 1/2 cup heavy cream
- 8 cups (or 2lbs) powdered sugar
- Toppings:
- Girl Scout Tagalong Cookies (optional)
- Supplies:
- 9x13 inch sheet pan
- Offset Icing Spatula
- Pipping bags
- Pipping tip 1M
- Food Processor
- Thermometer (optional)
Directions
- Step 1
- PREP CAKE: Preheat the oven to 325°F. Generously grease a 9×13 inch cake pan.
- Step 2
- SHORTBREAD COOKIE CRUST: In a food processor, blend up the shortbread cookies until a fine powder forms. Add in the melted butter and stir until combined. Press the crust in the prepared baking pan and press firmly in an even layer with the bottom of a cup. Pre-baking is not required.
- Step 3
- WET INGREDIENTS: In a large bowl, whisk together the buttermilk, sour cream, eggs, oil, and vanilla until combined.
- Step 4
- COMBINE: Mix in the unsweetened cocoa powder and cake box mix. Whisk until throughly combined.
- Step 5
- BAKE: Pour the batter into the prepared pan. Bake for 27-30 minutes or until a toothpick inserted in the center comes out clean. Baking times vary, so keep an eye on yours. (Note: The cooled cake may slightly sink in the center. Cocoa powder is simply not as structurally strong as all-purpose flour and can’t hold up to all the moisture necessary to make a moist tasting chocolate cake). Remove from the oven and allow the cake to cool in the pan. Cool completely before decorating. As the cake is cooling, chocolate ganache and peanut butter buttercream. (Tip: I like placing my cakes covered in the refrigerator or freezer while I make my frostings and/or toppings. I do this so that when I spread the frosting on the cold cake, the cake doesn’t pull away and I have no issues with crumbs in the frosting.)
- Step 6
- FOR THE FROSTING: Using a hand-held mixer or stand mixer fitted with a paddle or whisk attachment, beat the butter on medium speed until light and fluffy, about 2 minutes. Add the peanut butter, vanilla extract, heavy cream, and salt with the mixer running on low. Slowly add the powdered sugar. Increase to high speed and beat for 3 full minutes. You can add more powdered sugar if frosting is too thin, more cream if the frosting is too thick, or a little more of salt if the frosting is too sweet. Makes about 4 cups of frosting.
- Step 7
- FOR THE CHOCOLATE GANACHE: Place chocolate chips and heavy cream in a microwave-safe bowl and microwave for 30 seconds. Stir well, and then return to microwave and heat in 15-second increments, stirring well in between, until chocolate is completely melted and smooth. Set aside.
- Step 8
- DECORATE THE CAKE: Evenly spread the peanut butter buttercream over the top of the cake using an icing spatula. I used about 2 cups of frosting. Place the cake in the freezer for 5 minutes. I like doing this so that when you pour the warm chocolate over the frosting it will set quicker. Next, evenly spread the chocolate ganache over the frosting using an icing spatula. Place the cake in the freezer again for another 5 minutes. Using a pipping bag filled with the peanut butter buttercream and a 1M pipping tip, pipe the design (see above) evenly all the way around the pan. Optional: You can also chop up some Tagalong cookies and sprinkle them evenly over the top of the cake. Slice and serve.
- Step 9
- Cover leftovers tightly and store in the refrigerator for up to 5 days.
