Sour Cream Coffee Cake
["1 pkg. yellow cake mix", "1 pkg. instant vanilla pudding", "1/2 pt. sour cream", "1/2 c. oil", "4 eggs", "3/4 c. sugar", "4 Tbsp. cinnamon", "1 c. chopped walnuts"]
["Cover with remaining batter and cinnamon mixture.", "Cut to marbleize with knife.", "Bake 1 hour at 350\u00b0.", "Cool. Do not invert pan."]
["yellow cake mix", "instant vanilla pudding", "sour cream", "oil", "eggs", "sugar", "cinnamon", "walnuts"]