Sift the cake flour with the baking powder into a large bowl. Add the salt and mix. Beat the egg yolks until they are light and lemon-colored and combine them with the milk and melted butter. Blend thoroughly and add to the dry ingredients, beating briskly. Beat egg whites to stiff peaks, but not dry, and gently fold them into the mixture. Pour the batter from a pitcher or a ladle onto a heated waffle iron, filling the iron only 2/3 full, and let it spread until the whole iron is covered. Cook until the waffle is puffed and golden-brown. Life the waffle from the iron with a fork.
For the Maple Butterscotch Syrup
1 cup dark brown sugar
1/3 cup butter
1/3 cup heavy cream
1 tsp maple flavoring
1/2 cup water
In a saucepan over medium high heat, mix dark brown sugar, butter, cream, and maple flavoring. Bring to a boil for 5 minutes without stirring. Remove the sauce from the heat and add the water, beating for 30 seconds. Serve warm.