hese aren’t very sweet AT ALL. If you’re into the sweet thing and don’t think syrup will do the trick, then add another tablespoon of sugar. Also, try to bring the eggs to room temperature; egg whites peak much easier at room temperature.
In a bowl whisk together the egg yolks, the ricotta, the sugar, and the zest, add the flour, and stir the mixture until it is just combined. In a bowl with an electric mixer beat the egg whites with a pinch of salt until they hold stiff peaks, whisk about one fourth of them into the ricotta mixture, and fold in the remaining whites gently but thoroughly. Heat a griddle over moderately high heat until it is hot enough to make drops of water scatter over its surface and brush it with some of the melted butter then turn down heat to medium. Working in batches, pour the batter onto the griddle by 1/4-cup measures and cook the pancakes for 2 to 3 minutes on each side, or until they are golden, brushing the griddle with some of the melted butter as necessary. Transfer the pancakes as they are cooked to a heatproof platter and keep them warm in a preheated 200°F. oven.
If they look a little soft in the middle, leave them on the pan a little longer, but just bring down the heat to low. You don’t want an egg white filled pancake!
Serve the pancakes with maple syrup.