confectioners (powdered) sugar for dusting top of cakes
Preheat oven to 450 degrees. Generously butter and lightly flour 8 4-ounce ramekins, custard cups or molds.
In the top of a double boiler, melt the butter and chocolate over low heat, stirring, until the chocolate is almost melted. Remove from heat and set aside.
With an electric mixer, beat together the eggs, egg yolks and sugar until light and thick. Slowly beat in the chocolate mixture, then the flour. Divide batter among ramekins. Place on a baking sheet and bake for 8 to 10 minutes. The center will still be quite soft but the sides will be set. Run a knife around the edges of the cake to loosen from the ramekin, invert each on to a dessert plate and let sit for around 10 seconds, then remove ramekin. Dust top with powdered sugar. Serve immediately with vanilla or coffee ice cream.
Variation: Leave cakes in ramekins and serve warm.
Make ahead: The cake batter can be prepared up to 8 hours before baking, covered and refrigerated. Pour into ramekins just prior to baking.