1 c butter
2 eggs
1 ½ tsp cinnamon
2 c flour
2 c sugar
4 tbsp cocoa powder
1 c Dr. Pepper
½ c buttermilk
1 tsp soda
1 tsp vanilla 

Heat butter, cocoa and Dr. Pepper. Mix eggs, sugar, buttermilk, soda and vanilla. Add Dr. Pepper combination to dry ingredients. Bake in 8 inch layer pans for 30 minutes and 350 degrees. 

Icing
¼ c margarine
¼ c Dr. Pepper
3 tbsp cocoa
1 box powdered sugar
½ tsp vanilla
chopped nuts, for garnish 
Heat margarine, Dr. Pepper and cocoa until well blended. Stir in remaining ingredients. Frost cake.