Wholemeal Waffles with Strawberry Cream Topping

For the batter: In a mixing bowl, beat the butter with the sugar until light and fluffy. Separate the eggs and beat the yolks with the butter mixture. Beat the egg whites with the salt until stiff peaks form. Combine the wholemeal flour with the baking powder and alternatley add the flour mixture and the yogurt to the the butter mixture, beginning and ending with the flour mixture. Add enough milk to form a smooth batter, Finally, fold in the egg whites. Brush a waffle iron with a little butter and cook the waffles according to the manufacturer's directions.