1 cup fresh or frozen blueberries or huckleberries (opt)
Preheat waffle iron.
Sift together the flour, baking powder, salt, and sugar in a bowl.
In a separate bowl, whisk together milk, 2 egg yolks, and vanilla. Pour over the dry ingredients and very gently stir until halfway combined. Pour in the melted butter and continue mixing very gently until combined.
In a separate bowl, beat the egg whites until stiff. Slowly fold them into the batter, stopping short of mixing them all the way through.
Very gently, fold blueberries or other berry into the batter. Make sure that if you are using frozen berries, that they are well drained.
Scoop the batter into your waffle iron in batches and cook according to its directions. Bake waffles until deep golden brown & crisp.
Remove and serve immediately with softened butter and warm syrup, jam, cinnamon & sugar or confectioners sugar!