To make cake, preheat oven to 350. Grease a 13 x 9 inch baking pan. In large bowl, sift together flour and sugar. In small pan, heat butter, cocoa, and cola just til mixture boils. Add marshmallow crème and stir til it’s melted into the chocolate. Pour this heated creamy mixture into the flour mixture and blend well. Add buttermilk, eggs, baking soda and vanilla. Beat by hand for about 1 minute to incorporate air into batter. Pour batter into prepared baking pan and bake for 30 to 40 minutes or til toothpick inserted in middle of cake comes out clean. This cake you frost hot, and it’s a leave in the pan, take to church supper kind of cake.