In a large mixing bowl, lightly beat eggs. Add milk, maple syrup, olive oil, vanilla and salt; whisk until well combined. Add whole wheat flour, mix well.Preheat waffle maker and make waffles according to your waffle maker's instructions. Amount of batter depends on the size of your waffle maker. I have similar to this non-stick one and used about 1/3 cup batter per waffle. If your waffle maker is cast iron you might have to spray it with cooking spray to prevent waffles from sticking but maybe not since batter has enough oil. Try one and see how it comes out.