In a large bowl, mix the flour, sugar, baking powder, and salt and mix with a spoon. Make a well in the center of the bowl.
Separately, in another medium bowl, add the milk, ricotta, eggs, and vanilla extract and mix with a fork or hand whisk until smooth.
To the milk add the lemon zest, lemon juice, melted butter and beat quickly with the same fork or hand whisk until everything is well integrated (the mixture may look like a curd but is is completely okay).
Immediately, add this milk mixture to the bowl with the flour and beat for 30 seconds until an homogeneous mixture that will look a little lumpy forms.
Place a large skillet over medium heat with some butter. Once it is hot, pour a large spoonful of the batter on it to make a pancake.
Cook for 2 minutes until the surface of the pancake is bubbly and puffs up a little. Flip and cook for another minute until golden brown on the other side. Repeat the process with the rest of the batter until you have approximately 10 pancakes.
Serve the pancakes hot with maple syrup or honey. They can also be served with fresh fruit or jam.