Devil's Food Cake with Midnight Ganache.
It was not cocoa, which TJ's apparently also sells, but a hot chocolate mix. I didn't really realize this until the cakes were already in the oven and I was measuring it out for the ganache and saw the sugar crystals. Thus, the cake wasn't as dark and rich as it could have been, but it was still the right kind of gooey all-American cake.
I'd actually made the cake component of this recipe once before, for Matt's father's birthday cake last summer. I paired it with a mocha Italian buttercream and some David Lebovitz style candied cherries (one of which betrayed me with pit fragments--grr). It's a very solid base cake for all kinds of shenanigans.
I have to get some more cocoa. Rose's Heavenly Cakes is nothing without cocoa.