In a large bowl, whisk together the flour, sugar, baking powder, baking soda, and salt. Make a well in the center.
In a separate medium bowl, whisk together the ricotta cheese, milk, egg yolks, melted butter, lemon zest, lemon juice, and vanilla extract until smooth.
In a small, impeccably clean bowl, beat the egg whites with an electric hand mixer until stiff peaks form (this is the secret to fluffy pancakes).
Pour the wet ingredients into the dry ingredients and stir gently with a spatula until just combined. The batter will be thick and slightly lumpy.
Gently fold the stiff egg whites into the batter in two additions. Do not overmix; it's okay if there are a few streaks of white.
Heat a cast-iron skillet or griddle over medium heat. Grease with butter. Pour 1/3 cup of batter per pancake. Cook until bubbles form on the surface and the edges look set (about 3 minutes).
Flip carefully and cook for another 2 minutes until golden brown. Serve immediately with warm maple syrup, fresh blueberries, and an extra dusting of lemon zest.