Fluffy Lemon Ricotta Pancakes

Whisk together flour, baking powder, sugar, and salt in a bowl. Combine ricotta (make sure its firm and not runny), milk, egg yolks, lemon zest and vanilla in a separate bowl. Beat the egg whites in an electric mixer until stiff. Add the dry ingredients to the ricotta and milk mixture, stirring gently until just combined. Whisk in a small amount of the egg whites to lighten the batter, then fold in the remaining whites. Heat a pan or griddle over medium-high heat, and brush the surface with melted butter. Use a ladle or measuring scoop (I used a 1/3 cup measure) to pour batter onto the griddle. Cook pancakes for about 3 or 4 minutes or until they begin to turn golden, then flip, cooking until both sides are golden brown.