Made these last night. Yum.

Individual Fallen Chocolate Cakes

1/2 cup butter
4 oz. bittersweet chocolate (not unsweetened)
2 eggs
2 egg yolks
1/4 cup sugar
2 teaspoons flour

In the top of a double boiler set over simmering water, heat the butter and chocolate together until the chocolate is almost completely melted. While that’s heating, beat together the eggs, yolks and sugar with a whisk or electric mixer until light and thick.

Beat together the melted chocolate and butter; it should be quite warm. Pour in the egg mixture, then quickly beat until combined. Butter and lightly flour four 4-oz. molds, custard cups or ramekins. Tap out the excess flour. Divide the batter among the molds. (At this point you can refrigerate the desserts until you are ready to eat, for up to several hours; bring back to room temperature before baking)

Preheat the oven to 450-degrees. Bake the molds on a tray for 6-7 minutes. The center will still be quite soft, but the sides will be set.
Let stand on counter 5 minutes to firm up a little more Invert each mold onto a plate, let sit another ten seconds. (Leap of faith here. They only need to have the sides strong enough. Too much "safe side" and the filling cooks and disappears.)

Unmold by lifting one edge of the mold; the cake should fall onto the plate. Serve immediately garnished with whipped cream, vanilla ce cream or on a puddle of raspberry sauce.