mix 2 c flour with 2 c sugar in a very large mixing bowl. The over medium high heat, bring to a boil (slowly) 1 c butter, 2 tbsp cocoa and 1 c cola drink. Remove from heat and pour over flour mixture. Then add ½ c buttermilk, 1 tsp baking soda, 2 lightly beaten eggs, 1 tbsp vanilla and 1 ½ c mini marshmallows. Then mix well and pour in a 13x9x2 pan that has been lightly greased and floured. Then bake in a pre heated 350 degree oven for 30-35 minutes. Let cool and add the icing with is a mixture of ½ c butter, 3 tbsp cocoa and 6 tbsp cola drink and 16 oz pkg powdered sugar. I tried this on 1/5/09 and it was awesome. The kids loved it. I doubled the recipe on the frosting. I also needed to cook the cake much longer than receipe called for. Also do not put too many marshmallows in cake as it just did not set up right. Cake is done when toothpick comes out clean.