In a large bowl, whisk together dry ingredients (flour, baking powder, sugar and salt).
In a separate large bowl, whisk together the eggs, milk, melted butter, vanilla extract, lemon juice and zest. Fold in the ricotta cheese and mix until just combined.
Slowly add the wet ingredients to the dry and fold until just combined and there are no bits of dry flour left (it's okay if the batter is lumpy). Depending on the amount of moisture in your ricotta, you may need to add a bit more milk to make the batter a bit thinner; it should be the consistency of a thin yogurt.
Heat a griddle or large skillet over medium heat with about 1 tbsp of butter. Once hot, use a 1/4 cup measuring cup to scoop the batter into the pan. Cook until the pancakes are beginning to form bubbles on the top and are golden brown on the bottom, 3-5 minutes. Then flip and cook another 2-4 minutes until the other side is golden.
Repeat with remaining batter, adding more butter to the pan between batches as needed, until all your pancakes are done. You can keep the pancakes you've already cooked warm in the oven set to "warm" until all of the are done. Serve warm with maple syrup or fruit puree.