I used this chocolate cake recipe from the Betty Crocker cookbook given to me for my 16th birthday.
COCOA FUDGE CAKE
2 cups cake flour
OR 1 2/3 cups all-purpose flour
1 ½ cups sugar
2/3 cup cocoa
1 ½ teaspoons baking soda
1 teaspoon salt
1 ½ cups buttermilk
½ cup shortening
2 eggs
1 teaspoon vanilla
Heat oven to 350°F. Grease and flour bottom and sides of 13x9-inch pan, two 8 or 9-inch round cake pans. In large bowl, beat all cake ingredients with electric mixer on low speed 30 seconds, scraping bowl constantly. Beat on high speed 3 minutes, scraping bowl occasionally. Pour into pan(s).
Bake rectangle 40 to 45 minutes, rounds 30 to 35 minutes or until toothpick inserted in center comes out clean. Cool rectangle in pan on cooling rack. Cool rounds 10 minutes; remove from pans to cooling rack. Cool completely. Frost with your chocolate frosting.