This is the recipe I use to make my cakes and cupcakes. I got it from a lady names Sally who made our wedding cake and it is amazing every time. It's always very rich and moist without falling apart and you can enhance the flavor of the cake mix or make a white cake any flavor you want just by altering the pudding flavor. I prefer to use Duncan Hines brand for this recipe
1 cake mix, any flavor (I prefer Duncan Hines)
1 small box pudding, any flavor that coordinates with the cake
1 cup sour cream or plain yogurt
1/2 cup oil
1/2 cup water
1 tsp vanilla
Combine all ingredients in a medium to large mixing bowl. Beat for 2 minutes with hand mixer. The batter will be very rich and smooth. Bake at 325 until inserted toothpick comes out clean. It will take longer to bake than what is listed on the box.