Easy Red Velvet Cake
["1 box Duncan Hines butter cake mix", "1 tsp. cocoa", "1 tsp. vanilla flavor", "1 c. buttermilk", "1 tsp. soda", "1 bottle cake coloring (small)", "1 stick butter", "1 Tbsp. vinegar", "3 eggs"]
["Mix cake mix with cocoa.", "Add vanilla, buttermilk, cake coloring, margarine and eggs.", "Blend until moistened.", "Add soda and vinegar; mix into cake mixture.", "Beat for 4 minutes at medium speed.", "Pour into 2 round pans and bake 25 to 30 minutes at 375\u00b0."]
["cake mix", "cocoa", "vanilla flavor", "buttermilk", "soda", "cake coloring", "butter", "vinegar", "eggs"]