Preheat your waffle iron and lightly coat it with non-stick cooking spray.
In a large mixing bowl, combine flour, sugar, baking powder, and salt. Whisk until evenly mixed.
In another bowl, whisk together eggs, milk, melted butter, and vanilla extract. Add citrus zest if using.
Pour the wet ingredients into the dry ingredients and stir gently until just combined. Let the batter rest for 5 minutes.
Pour about ½ cup of batter onto the preheated waffle iron and cook for 3-5 minutes until golden brown.
Serve hot with maple syrup, fresh berries, or whipped cream.
