What's Sour Cream Without Pudding?

I made the sour cream chocolate cake from the Betty Crocker cookbook. It looked promising. I was hoping it would be sort of fudgy.

The crackly crust had the potential of hiding a brownie-like inside.

But it turned out to be pretty dry. Maybe I shouldn't have swapped out the butter for shortening? I'm leaning toward taking a page from the last cake and added lots of pudding mix to the ingredient list!