Always the finest way to serve chocolate, this is often called chocolate volcano because of its rich, solid exterior and oozing saucy interior. Serve with whipped cream. The mixture can be made ahead and refrigerated. Remove from the fridge 30 minutes before baking to allow it to come to room temperature. Make sure the muffin tins are well greased for easy removal of the cakes. This makes more than 2 cakes, so if you can restrain yourself from eating them all, they make a decadent breakfast.