Easy and unfussy, this peanut butter chocolate sheet cake is comfort food in a casserole dish. Sheet cakes are great for a crowd, or dessert for a few days!
We don’t bake nearly enough sheet cakes, darlings. A sheet cake, like this peanut butter chocolate sheet cake, can be overlooked when we bake for the ‘gram. Or whatever your preferred social media. But sheet cakes are comforting, one of those relics of childhood that give you all the warm fuzzies coming out of the oven. It feels “home-y” to cut into a sheet cake, like wearing your favorite cardigan. I baked a sheet cake for friends a few weeks ago, and remembered to dust off this recipe.
This chocolate sheet cake recipe is a sour cream chocolate sheet cake. I like the flavor the sour cream adds to the cake, and the moisture. You won’t actually taste any sour cream, so don’t worry about that, but it does keep the sweetness in check. Balance is a good thing when the urge to pile on all the creamy peanut butter frosting strikes! Of course we give in, and top with the cutest little mini peanut butter cups, because we can. Mini peanut butter cups on top of fluffy peanut butter ice cream over a moist chocolate sheet cake is just right.
Bake this sheet cake in a 9×13″ glass casserole dish. I tried a smaller, cuter one, but the cake overflowed and I had no room for frosting. I also had to clean my oven. To me, sheet cakes should fit rather neatly in their dishes, with room for frosting, so you can cover the dish neatly for storage. Ideally with a lid, but to preserve our beautiful swaths of frosting, probably with plastic wrap. I didn’t want to crust the frosting at the corners. And no one should have to clean burnt chocolate cake out of the oven.
I found the mini peanut butter cups in the candy section of the grocery store. I’ve seen them in the baking section sometimes, so if you want to use them, check both places. If you don’t find them, don’t fret. Sub a mix of chocolate chips and peanut butter chips, or skip topping altogether, it’s just decoration on an already delicious cake. Enjoy, darlings!
Peanut Butter Cupcake Batter
- 1 cups brown sugar
- 4 tbsp unsalted butter, softened
- 1/3 cup smooth peanut butter
- 1 egg
- 1/4 cup neutral-flavored oil
- 3/4 cup buttermilk
- 1 tsp baking powder
- 1/2 tsp baking soda
- 1/2 tsp salt
- 2 cups all-purpose flour
- 2 tsp vanilla extract
- 16 ounces jelly or preserves, flavor is up to you, grape or strawberry are our favorites
Peanut Butter Frosting
- 12 tbsp unsalted butter, softened
- 1/2 cup smooth peanut butter
- 3 cups powdered sugar
- 1/2 tsp vanilla extract
Optional glaze and topping
- 1/4 cup water
- 2 tbsp preserves, pull from the filling
- 3 tbsp sugar
- chopped peanuts
- Preheat the oven to 350 F and place liners into 18 cupcake wells in 2 dozen cupcake pans. Set aside.
- Cream together the butter, sugar, and peanut butter in a mixing bowl on medium speed until light and fluffy. Scrape the sides of the bowl.
- Stir in the egg and vanilla extract.
- In a separate bowl, sift together the dry ingredients and then stir half into the peanut butter mixture. Add the buttermilk, stir, then add the rest of the dry ingredients and mix until just combined.
- Fill each cupcake liner about 2/3 full (I use a medium cookie scoop to "measure") and bake for 25-30 minutes until a tester inserted in a cupcake comes out clean and the center of the cupcake springs back lightly when touched.
- Remove the cupcakes from the oven and cool completely before proceeding.
- Fill the cupcakes by placing the preserves or jelly in a piping bag fitted with a filling tip. Insert the tip into the center of a cooled cupcake and apply pressure. Count to 3, remove the tip. Repeat with the remaining cupcakes
- To make the frosting, cream together the butter and peanut butter until light and fluffy on medium speed. Scrape the sides of the bowl.
- Add the powdered sugar, one cup at a time, mixing at low speed. Stir in the vanilla extract. Pipe or spread the frosting onto the cupcakes.
- If you'd like to make the glaze, melt the sugar, jelly, and water in a small saucepan over medium low heat. Whisk together until smooth and then remove to a heat-safe bowl to cool for about 10 minutes. Drizzle over the cupcakes, top with chopped peanuts.