Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9x13 inch baking pan.
In a large bowl, cream together the butter and sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla. Combine the cocoa, flour, baking soda, baking powder and salt; stir into the creamed mixture alternately with the buttermilk. Fold in the chocolate chips and walnuts. Spread evenly into the prepared pan.
Bake for 30 to 35 minutes in the preheated oven, or until a toothpick inserted into the center of the cake comes out clean. Let cool in the pan before frosting.
Frost cake with Chocolate Frosting.
Interesting Facts
This cake is perfect for special occasions such as birthdays, anniversaries, or any other celebration!
The cocoa powder in this cake adds a rich flavor and deep chocolate color.
This cake can be made in advance and stored in the fridge for up to 3 days.