01 - Preheat waffle iron according to manufacturer's guidelines
02 - Whisk flour, sugar, baking powder, baking soda, and salt in large bowl
03 - Mix egg yolks, milk, ricotta, melted butter, lemon zest, lemon juice, and vanilla until smooth
04 - Beat egg whites in clean bowl until stiff peaks form
05 - Add wet ingredients to dry ingredients and stir gently until just combined, avoiding overmixing
06 - Carefully fold beaten egg whites into batter until fully incorporated
07 - Lightly grease waffle iron and pour 1/2 to 3/4 cup batter per waffle; cook 3-5 minutes until golden brown and crisp
08 - Serve warm with maple syrup, fresh berries, or powdered sugar