Wonderful Banana Cake - Allrecipes.com Wow, this is fabulous! I used a Duncan Hines butter yellow cake mix plus used 3 bananas, added 1/2 tsp of cinnamon and 1 cup of sour cream. This was so very moist and so tasty!!! Delicious! I baked for 40 min in a preheated oven and it was perfect! Thanks so much for an easy and tasty cake!