For the cake:
- 2 cups flour
- 2 cups sugar
- 1/4 teaspoon salt
- 2 sticks butter
- 1/2 cup creamy peanut butter
- 1 cup boiling water
- 1/2 cup buttermilk
- 2 eggs, beaten
- 1 teaspoon baking soda
- 1 teaspoon vanilla
For the frosting:
- 1 3/4 sticks butter
- 4 heaping tablespoons cocoa
- 6 tablespoons milk
- 1 teaspoon vanilla extract
- 1 pound minus 1/2 cup powdered sugar
- 1/2 cup pecans, finely chopped
- Preheat the oven to 350 degrees F.
- In a mixing bowl, combine the flour, the sugar, and the salt.
- In a saucepan, melt 2 sticks of the butter
- Add the peanut butter to the melted butter and stir them together.
- Add the boiling water to the peanut butter mixture and allow it to boil for 30 seconds.
- Transfer the peanut butter mixture from the heat, pour it over the flour mixture, and stir to slightly cool it.
- In a measuring cup, add the buttermilk, the eggs, the baking soda, and 1 teaspoon of the vanilla extract and stir to combine.
- Pour the buttermilk mixture into the batter and stir to combine.
- Evenly spread the batter into an 18×13-inch sheet pan and bake the cake until a toothpick inserted into the center comes out clean, about 20 minutes.
- Melt the remaining butter in a saucepan.
- Add the cocoa to the butter and stir to combine.
- Turn off the stove-top heat and stir the milk, the vanilla extract, and the powdered sugar into the cocoa mixture.
- Add the pecans to the icing mixture and stir until they are evenly distributed.
- Pour the icing over the cake.
- Slice and serve