It's essentially a brownie, but you cook it just long enough to form a crisp top layer so you have gooey chocolate center left.
Ours ended up a bit more firm than they are traditionally, but we had no trouble eating it anyway.
We enjoyed cooking in that night- Eric made a thai curry just for fun since it will be a few weeks before we have access to a kitchen again. It's sort of a relief to cook in when you've been eating out every single meal.
What are you having for dinner tonight?