In a medium mixing bowl stir together flour, sugar, baking powder, and salt. Make a well in center of mixture; set aside.
Separate egg yolks and whites. In a medium bowl, beat egg whites until they are stiff. Add egg yolks and stir in milk, oil, and vanilla. Add egg mixture all at once to flour mixture. Stir just until moistened – do not over-mix.
Pour batter onto grids of a preheated, lightly greased waffle iron (use a regular or Belgian waffle maker). Close lid quickly; do not open until done. Bake according to manufacturer’s directions. Remove waffle from waffle iron with a fork. Repeat with remaining batter. Serve warm & fresh off the waffle iron.