In a medium bowl, combine the flour, baking powder, baking soda, and salt. Set aside.

In a large bowl, whisk the milk and eggs. Once the eggs have fully incorporated into the liquid, add the ricotta cheese, melted butter, sugar, and vanilla. Mix until the ricotta cheese is well incorporated into the liquid ingredients. If you want to zest a lemon and add its juice, now is the time.

Add the dry flour mix to the wet ingredients bowl and gently mix until they're combined. A few lumps in the batter are ok.

Preheat the waffle iron. Once hot, grease the waffle grids with spray or brush oil or butter onto them. Pour ¼ to ⅓ cup of batter per waffle (this varies by waffle iron). Although the batter is thick, when pressing down, no batter should ooze out on the sides.

Cook the waffles for 2 to 3 minutes. Wait to open the waffle until the steam stops venting out from the sides. When the waffles are ready, remove them from the waffle iron onto a plate. Keep them warm in the oven, in a pancake keeper, or covered with a clean kitchen towel. Repeat the process with the remaining batter.

Leftover cooked waffles can be kept in the fridge in a zip bag or an air-tight container for up to 3 days and frozen for up to 3 months.