Mix the ricotta cheese, egg yolks, sugar, lemon zest, lemon juice, buttermilk and vanilla in a large bowl.
Mix in the flour, baking soda and salt, being careful not to over-mix. It's OK if there are a few lumps in the mixture.
Meanwhile, beat the egg whites in a bowl until frothy and no longer opaque.
Fold the egg whites into the pancake batter, being careful not to over-mix so the egg whites don't deflate.
Heat a nonstick skillet over medium-low heat and brush it with butter.
Pour a portion of the pancake batter (⅛ to ¼ cup, depending on size preference) in the pan and cook until golden brown (1-2 minutes per side).
Remove and place on a plate. Place finished pancakes on a plate in a 200 degree oven to keep them warm while remaining pancakes are completed. Repeat until all batter is gone.
Notes
Add additional lemon zest if you like the pancakes to have a stronger lemon flavor.
Substitute orange juice and peel for the lemon to make orange ricotta pancakes.
Don't over mix the batter as your pancakes will become tough. It's ok to leave a few lumps in the batter.
Gently fold in the egg whites so they don't deflate.
Use a non-stick skillet or a well seasoned cast iron skillet and make sure to add more butter periodically to prevent pancakes from sticking.
If pancakes start to brown too quickly or burn, turn the heat down to medium-low.