About 2 tablespoons of butter helps.
Linda C

Try this:

I use it to make wedding cakes when I don't want to bake from scratch.

I would halve the recipe for making it at home. You also don't need the inverted flower nail if you are using smaller pans. Do not fill pans more than 2/3 full.color="red">

Ingredients

* Ingredients:
2 boxes Duncan Hines Dark Chocolate Fudge cake mix
2 2/3 c. water
1/2 c. vegetable oil
6 large or extra large eggs
16 oz. sour cream
2 cups all-purpose flour
2 cups granulated sugar
1 1/2 tsp salt
1 Tbsp vanilla extract
1 Tbsp instant coffee

Instructions

1. Preheat oven to 325 degrees F.Prepare cake pans by spraying generously with original Pam. Place an inverted flower nail in the center of each pan and spray with Pam as well.
2. Add cake mix, flour, sugar, and salt to mixing bowl and stir with a whisk to mix and de-clump the cake mix. Dissolve coffee granules in room temperature water. You may also use 2 2/3 cups cooled strong black coffee in place of the water and instant coffee if you prefer. Add remaining ingredients to mixing bowl and mix on low speed for one minute. Stop, scrape bowl, and mix for 2 minutes on medium speed.
3. Pour into prepared pans and bake on middle rack of oven. Your cakes are done with a toothpick inserted in the center comes out with a bit of crumb clinging to it, and the cakes are just starting to pull away from the sides of the pans. Let cool for half an hour in the pan, then invert onto cooling racks to cool to room temp.
4. Wrap cakes in plastic wrap after cooling to prevent cakes from drying out. These cakes freeze really well. Wrap cakes well with plastic wrap and then with foil, and place in freezer. For long-term storage (more than 2 weeks), place wrapped cakes in a paper grocery sack. The paper sack will keep freezer odors out of your cakes. When you are ready to thaw them, remove cakes from paper sack and leave on counter overnight in plastic/foil.

I read somewhere to add 2 T. mayo to cake mixes to make them taste homemade. I have done it and think it makes them more moist.

Bob - here's my go-to recipe for ANY cake mix:

1 cake mix (18.5 oz.)
1 cup whole milk (can use 2% but NOT skim)
1 stick butter, melted
2 tsp. vanilla
3 eggs
(if I'm making a chocolate cake, I add 4 Tblsp. cocoa)

Preheat oven to 350° F. Grease and flour two 8-inch round cake pans. In large mixing bowl, combine ingredients listed above. Beat just until blended, and no lumps remain. Pour into pans and bake at 350° F. for 27-29 minutes or until cake tests done.

I actually was given this by a friend who watchers her weight...I actually thought it was good as did my family. RECIPE: package of duncan hines chocolate cake and (1) 12oz can of diet cherry coke... mix and bake according to box. Do not use any other ingredient other than the soda and cake mix! For those on weight watchers the 9x12 pan makes 12 servings at 2 points a serving....diet coke can be used also & the cake is surprisingly moist and low fat!