Vintage Peanut Butter Cake & Chocolate Frosting

Enjoy a fluffy, moist old fashioned slab cake ready in only 30 minutes. My quick, easy peanut butter cake with a gooey chocolate frosting is just the recipe you're looking for. Everything comes together in a saucepan, even the frosting, which is smothered on the freshly-baked sheet cake to make a crackly, warm chocolate glaze on top. Grab a fork and dig in!

Prep Time 10

Cook Time 23

Total Time 33

Servings

Author Melissa Erdelac

Ingredients

Peanut Butter Cake

½ cup (113 g) unsalted butter
1 cup (220 g) water
½ cup (129 g) peanut butter
2 cups (400 g) sugar
2 cups (292 g) all-purpose flour for gluten free I recommend Cup4Cup gluten free flour
½ teaspoon baking soda
½ teaspoon salt
2 eggs
½ cup (123 g) milk
1 teaspoon vanilla extract

Chocolate Frosting

½ cup (113 g) (1 stick) unsalted butter
6 tablespoons unsweetened cocoa powder
6 tablespoons sour cream
1 teaspoon vanilla extract
3 ½ cups (420 g) powdered sugar
¼ cup (36 g) chopped peanuts optional

Instructions

Peanut Butter Cake:

Preheat oven to 350ºF. Grease a 10X15" jelly roll pan. (For 9X13" pan see recipe notes.)
In a large saucepan melt butter over medium heat. Add water and peanut butter and bring to a boil. Remove from heat and stir in sugar. To the saucepan add flour, baking soda, and salt. Stir until well blended.
½ cup unsalted butter, 1 cup water, ½ cup peanut butter, 2 cups sugar, 2 cups all-purpose flour, ½ teaspoon baking soda, ½ teaspoon salt
In a small bowl or large liquid measuring cup, whisk together eggs, milk, and vanilla extract. Add liquids to saucepan and stir until very well combined and smooth. Pour into prepared pan and bake 23-25 minutes, rotating pan once during baking. Cake is done when a toothpick inserted in middle comes clean. (For 9X13" pan see recipe notes). During the last few minutes of baking, make the chocolate frosting.
2 eggs, ½ cup milk, 1 teaspoon vanilla extract

If using gluten-free flour, let the cake rest 10 minutes before baking. This gives time for the GF starches to hydrate and builds the cake's structure so it doesn't sink after baking.

Chocolate Frosting

In a medium saucepan add butter and cocoa powder. Stir together over medium heat until butter melts and mixture is very smooth.
½ cup (1 stick) unsalted butter, 6 tablespoons unsweetened cocoa powder
Remove from heat and stir in sour cream and vanilla extract. Gradually stir in powdered sugar until frosting is smooth and no lumps remain. Immediately pour on warm cake and spread evenly. Immediately sprinkle on optional chopped peanuts. Eat warm to experience cake heaven.
6 tablespoons sour cream, 1 teaspoon vanilla extract, 3 ½ cups powdered sugar

Notes

9X13-inch baking pan

The ingredient amounts will stay the same, but the cake will have to bake longer. Start checking around 30-35 minutes. The middle should be set and spring back when lightly touched. A toothpick inserted in the middle should come out clean.

Peanut Butter Cake recipe adapted from All Recipes and chocolate frosting from The Food Charlatan

Nutrition