Belgian Waffles

Dissolve yeast in water in large bowl. Stir in flour, milk, eggs, yolks, butter, granulated sugar and salt until smooth, about 2 minutes. Let rise covered and warm place until doubled, about 30 minutes. Stir down batter. Beat egg whites until stiff peaks form. Fold into batter.

Brush inside of Belgian waffle iron lightly with oil. Heat on both sides over medium-high heat. Pour about 1 1/4 cups of the batter evenly onto bottom of iron; close iron. Bake 1 minute; turn; bake until golden, 2 to 3 minutes. Remove from iron; keep warm. Repeat with remaining batter; sprinkle with powdered sugar.