Stir in powdered sugar until dissolved. Stir in eggs, egg yolks, and vanilla. Stir in flour.Fill each ramekin with an even amount of the batter. Bake at 475˚ for 17-19 minutes or until tops are no longer shiny.
Remove and let cool. Loosen each cake by running a butter knife around the edge of the ramekins. Carefully, turn cakes out onto a plate. Gently shake to loose if necessary being careful not to break the cake!