Separate the yolks from the whites. Beat the egg whites until they form stiff peaks and set aside. Mix the milk, melted butter, sugar, and yolks in a medium bowl. Beat until the sugar dissolves. Put all the dry ingredients (flour, baking powder, and salt) in a large bowl and add the previously mixed wet ingredients. Mix well all the ingredients until the dough has no lumps. Then, with a wooden spoon, mix the beaten egg whites set aside with the dough in folding motion until they form stiff peaks. At this point, you must not beat it or the dough will not rise.
Put the mixture in the waffle maker for 2 to 3 minutes.
Put a spoonful of mixed berries over the waffle, decorate with powdered sugar.