Whisk dry ingredients: Place flour, baking soda, and salt in a large bowl and whisk until combined. Set it aside.
Mix Wet ingredients: In a seperate bowl, whisk together ricotta cheese, egg yolks, milk, lemon zest, lemon juice, vanilla extract, and butter until it is just combined. Set it aside.
Gently pour and stir the ricotta mixture into the dry ingredients. Do not over mix.
Using a hand mixer, whisk egg whites for 1 minute in medium-low speed. Increase the speed to medium and whisk until foamy for 1 more minute. Slowly add the sugar and whisk until soft peaks form (it will be very silky) for 1-2 minutes.
Gently whisk 1/3 of the egg whites and sugar mixture into the flour and ricotta mixture.
Using a spatula, fold in the rest of the egg whites and sugar mixture into the batter making sure to be gentle to not to deflate all the air we incorporated into the egg whites.
Preheat the oven to 200 degrees F.
Heat 1 teaspoon vegetable oil in a 12-inch non-stick skillet in medium heat. Using a sheet of paper towel, wipe out the excess oil. Measure 1/4 cup* of the batter and portion it in 3 places leaving a couple of inches around each pancake. Let it cook 2 minutes, flip, and cook each pancake for another 1 minute or until the edges are set. Repeat it for the rest of the batter.
As you are working on cooking the rest of the batter, place cooked pancakes on a baking sheet in a single layer to keep them warm.
Serve with blueberry sauce, fresh blueberries or any other fresh fruit.