Sift together the flour, baking powder, salt and sugar into a mixing bowl.
Combine the milk and cream and stir into the flour mixture.
Beat the egg yolks until pale yellow.
Stir the egg yolks into the batter with the melted butter.
Set aside and allow to stand for one hour.
Beat the egg whites until stiff and gently fold into the batter.
Fill a hot lightly oiled waffle iron two-thirds full with the batter and cook until steam no longer appears.