I am looking for a great doctored chocolate cake from a mix. I have been using sour cream instead of oil, and mixing espresso powder with the water, and there is a horrible chemical aftertaste. 
Can anyone suggest a good recipe that I can use? I make and sell cakes from home and use everything from buttercream to fondant so I need a pretty firm cake, not soft and fluffy. Thanks! 
Istart with DH or BC Dark Chocolate, or Chocolate Fudge (any of the darker recipes) add an extra egg( equaling 4 eggs), 1/2 C butter, buttermilk instead of the water listed on the box and a chocolate fudge pudding mix. If you want it even chocolatier you can add a half a bag of mini chocoalte chips. Everyone loves this cake and it is a little denser than if you use oil and water, not quite as fluffy, works great for decorating.
do you melt the butter?
No, but I either use room temp butter or soften it in the microwave before adding it.
Oh and I usually use a flower nail in the middle of the pan to get it to cook evenly and cook at 25 degrees lower than what the box says to. Might take a little longer to cook, but comes out much more evenly done.
Have you tried different brands? One store brand here has very little chemical taste to it. The chocolate flavor is a little weak, but adding the box of pudding helps it. Using buttermilk sounds like one way to increase the flavor of a weak cakemix.
These are old bundt recipes. Some people think the cakemix doctor chic invented adding pudding to a cakemix. 
Happy baking!
#1
Choc cake mix
inst choc pudding
1 cup sour cream
1/2c warm water
1/3c veg oil
4eggs
1 1/2c choc chips
bake @ 325 for 55-60min
#2
choc cake mix
inst choc pudding
1c water
1/3c softened butter
4 eggs
bake @ 325 for 55-65min
Quote by @%username% on %date%
%body%