Preheat a waffle iron according to manufacturer's instructions. Combine flour, beer, butter, milk, egg yolks, honey, and vanilla in a large bowl; stir until the mixture is smooth. In a separate bowl, beat egg whites until stiff peaks form. Gently fold egg whites into batter.
Spray preheated waffle iron with non-stick cooking spray. Ladle the batter into waffle iron. Cook the waffles until golden and crisp. Serve immediately.