Old Timey Chocolate Cake
["1 box yellow cake mix", "1 stick margarine", "1 tsp. vanilla flavoring", "2 eggs", "1/2 pt. sour cream", "2 Tbsp. cocoa"]
["Mix and pour into greased 9 x 13-inch pan.", "Cook at 350\u00b0 until done."]
["yellow cake mix", "margarine", "vanilla flavoring", "eggs", "sour cream", "cocoa"]