I went for another mug cake tonight as a "for one" dessert while the hubby was at class: chocolate peanut butter mug cake. And it was good.
I didn't do the peanut butter mousse or the fudge sauce, because I was running a little low on calories that night, but it was still really good and really chocolatey. (You can see from the recipe in the link that it has more chocolate than flour!) The only thing I would change for next time is that I might under-microwave it a little bit next time, or serve it with a big swath of peanut butter on top.
Mmm. Mug cake.