Separate the eggs. Beat the butter with the sugar for 2-3 minutes until fluffy, then stir in the egg yolks. Mix the flour with the baking powder and a pinch of salt and add to the yolk mixture. Pour in the milk gradually while stirring. If the dough is too thick, mix in some more milk. Beat the egg whites until stiff and fold into the mixture.
Heat the waffle iron and brush with butter. Bake about 10 golden brown waffles. While still hot, dust with powdered sugar. Serve immediately with whipped cream, fruit preserved, ice cream or fresh fruit.