In a medium bowl, whisk the egg yolks, buttermilk, ricotta, lemon juice and vanilla until smooth and combined. Slowly drizzle in the melted butter while whisking. Carefully fold in the egg whites with a rubber spatula until just combined.
Pour the wet mixture over the dry mixture and fold until just combined, don’t over mix (there will still be plenty of lumps). This is a thick batter, but you can thin it out if you like with more lemon juice or a bit of water to get consistency you prefer.
Heat an electric griddle to 375 degrees (or use a large heavy-bottomed nonstick skillet).
Add a small amount of butter or oil to the griddle and spread with a paper towel until no visible butter or oil remains.
Use a 1⁄3 cup dry measuring cup to place 4-6 pancakes in the on the griddle and cook until bubbles start to appear on top and the bottoms are golden brown, about 2 minutes.
Carefully flip the pancakes and cook on the second side until golden brown and completely set, about 2 minutes longer.
Serve the pancakes immediately, or keep warm on a wire rack set on a rimmed baking sheet in a warm oven. Serve with warm maple syrup and butter.