In a large bowl, combine the flour, sugar, baking powder and salt. In another bowl, whisk the egg yolk, milk, orange juice, butter, orange zest and extract; stir into dry ingredients just until combined. In a small bowl, beat egg whites until stiff peaks form; fold into batter. Fold in blueberries.
Bake in a preheated waffle iron according to manufacturer's directions until golden brown. Sprinkle with confectioners' sugar.