Chocolate Peanut Butter Sheet Cake
One of the ultimate flavor combos in one decadent cake! Chocolate and peanut butter are baked together in a single cake topped with rich chocolate ganache, Reese's Pieces, and peanut butter cups.
Around Halloween, I'm always trying to think of recipes that will help use up some of the extra candy that people may have lying around. Because, let's face it, it can be a little too tempting to have a bowl of candy hanging out in the living room.
Enter this Chocolate Peanut Butter Sheet Cake: a moist and scrumptious cake that you can use to utilize any extra peanut butter candy you have around. Peanut butter and cocoa powder are mixed into this cake with a whipped chocolate ganache on top. Everyone will love this, and your entire home will smell like chocolate when you bake this!
Looking for another chocolate and peanut butter dessert recipe? Try these Reese's Pieces Chocolate Cake Mix Cookies made with only 5 ingredients. My husband says they are the BEST cookies he's ever had!
Table of contents
Ingredients You'll Need
You'll need the following for this cake:
- Natural cocoa powder, such as Hershey's Natural Cocoa Powder.
- Freshly boiled water. I like to mix this with the cocoa powder to bloom it for maximum chocolate flavor.
- All-purpose flour, spooned and leveled or weighed with a digital kitchen scale.
- Baking soda and baking powder
- Kosher salt
- Granulated sugar
- Oil. I use canola oil, but vegetable oil will also work.
- Vanilla extract. I like to use imitation vanilla.
- Creamy peanut butter. Avoid natural peanut butter because it has a lot of oil in it.
- Room temperature eggs. You want them to be the same temperature as the other ingredients for an evenly baked cake.
- Semi-sweet chocolate chips - I used Nestle Tollhouse Chocolate Chips.
- Heavy whipping cream. Room temperature is best so the ganache melts faster when you zap it in the microwave.
- Reese's Pieces and chopped peanut butter cups for the top.
Equipment and Supplies
You'll need the following:
- 9x13 baking pan or dish - I used a USA light metal pan. Baking time may need to be adjusted for a ceramic baking dish.
- Cooking spray to grease the pan, if the pan is not a nonstick. You don't want to spray a USA Pan or it will ruin the nonstickiness.
- Small, medium, and large mixing bowls.
- Whisk
- Electric mixer
- Digital Kitchen Scale - Optional, but I use it to weigh the dry ingredients and peanut butter.
Step by Step Directions
Cake:
Preheat the oven to 350°F, and grease a 9x13 baking dish or pan with butter or shortening. Set aside.
Stir the cocoa powder and hot water together in a medium bowl until the cocoa has dissolved and the mixture is smooth. Set aside to cool slightly.
Whisk together the flour, baking powder, baking soda, and salt in a medium bowl, and set aside.
Combine the granulated sugar, oil, and vanilla extract in a large bowl, and mix with an electric hand mixer until fluffy. Mix in the peanut butter and cocoa and water mixture until smooth, then add the eggs and mix until well combined.
Gradually add the dry ingredients to the wet ingredients, and mix until the batter is smooth and no streaks of flour remain. The batter will be thick and wet. Pour the batter into the prepared baking pan, and spread it into an even layer.
Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean and the cake bounces back quickly when lightly pressed in the middle. Remove from the oven and let the cake cool to room temperature in the pan before frosting.
Frosting:
Combine the chocolate chips and heavy whipping cream in a small microwave-safe bowl. Heat in 30-second increments, stirring after each one, until completely melted and smooth. Cover and refrigerate for at least 1 hour or until the ganache is chilled but soft and scoopable, similar to peanut butter.
Once chilled, whip the ganache with an electric hand mixer until it lightens in color and reaches a fluffy, spreadable frosting consistency.
Spread the whipped ganache evenly over the cooled cake. Sprinkle the Reese's Pieces and chopped peanut butter cups evenly over the top while the frosting is still soft, pressing gently so they adhere.
Slice into 12 pieces and serve at room temperature.
Frequently Asked Questions
There are a few! You can chop up a semi-sweet chocolate baking bar (a 4-ounce bar) instead of using semi-sweet chocolate chips. You can use any peanut butter candies on top or even use peanut butter chips. If you swap the natural cocoa powder for Dutch processed cocoa powder, the color of the cake will be darker, and it may have a milder chocolate flavor.
Store it in an airtight container or wrap it tightly with plastic wrap. It can stay at room temperature for up to 2 days, or you can store it in the refrigerator for up to 5 days. Enjoy it chilled or bring it to room temperature.
Yes! I recommend freezing the cake before adding the ganache and peanut butter candies on top for the best results. Wrap it in both plastic wrap and foil to prevent freezer burn, and you can keep it in the freezer for up to 3 months. Thaw it out overnight in the fridge before frosting and serving.
It's actually quite noticeable, but not overpowering. The chocolate and peanut butter flavors are very well balanced. I chose to do it this way so you wouldn't have to make two different frostings for this cake. The peanut butter candies on top also add a lot of peanut butter flavor.
Why You Should Bloom Your Cocoa Powder First
For all of my baked chocolate desserts, I like to bloom the chocolate in freshly boiled water before I mix it into the cake batter. This will give the cake a stronger chocolate flavor than just mixing in the cocoa powder and pouring the hot water in at the end of the mixing process. I learned that from a friend who used to bake cakes for a living!
Blood Sugar Impact
Chocolate Peanut Butter Sheet Cake
Equipment
- 9x13 baking pan or dish
- Cooking spray
- Small, Medium, and Large mixing bowls
- Whisk
- Electric mixer
Ingredients
Cake:
- ⅔ cup natural cocoa powder 60 grams
- 1 cup hot water
- 2 cups all-purpose flour, spooned and leveled 240 grams
- 1 teaspoon baking powder
- ½ teaspoon baking soda
- ½ teaspoon kosher salt
- 1 ¼ cups granulated sugar 250 grams
- ½ cup oil canola or vegetable
- 1 teaspoon vanilla extract
- ¾ cup creamy peanut butter 180 grams
- 2 large eggs room temperature
Ganache Frosting:
- 1 ½ cups semi-sweet chocolate chips 265 grams
- 1 ½ cups heavy whipping cream
Toppings:
- ½ cup Reese's Pieces or peanut butter candies
- ½ cup chopped peanut butter cups
Instructions
Cake:
- Preheat the oven to 350°F, and grease a 9x13 baking dish or pan with butter or shortening. Set aside.
- Stir the cocoa powder and hot water together in a medium bowl until the cocoa has dissolved and the mixture is smooth. Set aside to cool slightly.
- Whisk together the flour, baking powder, baking soda, and salt in a medium bowl, and set aside.
- Combine the granulated sugar, oil, and vanilla extract in a large bowl, and mix with an electric hand mixer until fluffy. Mix in the peanut butter and cocoa and water mixture until smooth, then add the eggs and mix until well combined.
- Gradually add the dry ingredients to the wet ingredients, and mix until the batter is smooth and no streaks of flour remain. The batter will be thick and wet. Pour the batter into the prepared baking pan, and spread it into an even layer.
- Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean and the cake bounces back quickly when lightly pressed in the middle. Remove from the oven, and let the cake cool to room temperature in the pan before frosting.
Frosting:
- Combine the chocolate chips and heavy whipping cream in a small microwave-safe bowl. Heat in 30-second increments, stirring after each one, until completely melted and smooth. Cover and refrigerate for at least 1 hour or until the ganache is chilled but soft and scoopable, similar to peanut butter.
- Once chilled, whip the ganache with an electric hand mixer until it lightens in color and reaches a fluffy, spreadable frosting consistency.
- Spread the whipped ganache evenly over the cooled cake. Sprinkle the Reese's Pieces and chopped peanut butter cups evenly over the top while the frosting is still soft, pressing gently so they adhere.
- Slice into 12 pieces and serve at room temperature.
Notes
- I prefer to bloom the cocoa powder in hot water before mixing it into the cake batter. The chocolate flavor will be stronger.
- I was inspired to create a cake with Reese's cups and candies when I was thinking of recipes that would use up Halloween or extra candy.
- Having ingredients that are all at room temperature will ensure that the cake will be evenly baked.
