I have several boxes of yellow cake mix that I would like to use up. My family prefers chocolate cake though. I would assume that I can just add cocoa to the mix to convert to chocolate, but I'm not completely sure how much to add without messing with the structure of the cake. Hope that makes sense. Any ideas.

I've done this before. I'm not 100% positive but I'm pretty sure I added 1/4 c. cocoa to the dry mix first. It came out really well I remember that! HTH

You didn't have to add any extra oil to compensate for the dry cocoa?

I don't believe I did... maybe someone else has done it and can put in their 2 cents.. but I'm 99% sure all I did was toss in some cocoa powder, and it was fine. I always bake box mix cakes for less than the time on the box, slightly underbaking I guess..., and they come out moist and I don't think this was any exception.

Good Luck!

I have not added cocoa, but when I make walnut cake out of the yellow cake mix, I add 3 tablespoons ground nuts, and 3 tablespoons sour cream. I think you could add some sour cream if you have any concerns about dryness.

This is a chocolate cake recipe I use all the time. It uses a yellow cake mix as a base. It tastes awesome!

http://cakecentral.com/recipes/1988/blue-ribbon-moist-and-fudgey-chocolate-cake

Thanks for the help. I think I may try each of these ideas just to see which I like better. This is why I love this site so much. You can get an answer for just about anything.