One Bowl Chocolate Cake
2 cups all-purpose flour
2 cups sugar
¾ cup cocoa powder
2 teaspoons baking soda
1 teaspoon baking powder
½ teaspoon salt
2 large eggs
1 cup buttermilk
½ cup vegetable oil
2 teaspoons pure vanilla extract
1 cup very hot water
Easy Chocolate Buttermilk Frosting
½ cup butter, (1 stick)
4 tablespoons cocoa powder
6 tablespoons buttermilk
1 teaspoon pure vanilla extract
16 ounces powdered sugar, or up to 4 cups, as needed to reach desired consistency
½ cup finely chopped pecans or walnuts, optional
For the Cake
Preheat oven to 350 degrees F. Coat a 13- x 9-inch baking dish with nonstick cooking spray.
In a large mixing bowl, whisk together the flour, sugar, cocoa powder, baking soda, baking powder, and salt. Using an electric hand or stand mixer, beat in eggs, buttermilk, oil, and vanilla. Add hot water and mix until combined. Batter will be quite thin.
Pour batter into prepared baking dish. Bake for 35 to 40 minutes or until a toothpick inserted in center comes out clean. Cool completely in pan before frosting.
For the Frosting
Melt butter in a large saucepan over MEDIUM heat. Whisk in cocoa powder, buttermilk and vanilla. Turn heat to LOW and whisk in powdered sugar, using as much as you need until you’ve reached the desired consistency. It should be thick but pourable. Continue whisking vigorously until smooth. Stir in chopped nuts, if using, or reserve them to use as a garnish on top of frosting.
Immediately pour frosting over cake and use an offset spatula or butter knife to spread it out evenly over the surface. Garnish with nuts, if desired. Allow to set for a few minutes before slicing and serving the cake.