For the dough: beat the egg whites with a pinch of salt, when they are well beaten, add the vanilla sugar, the yolks, then the melted butter and the milk, gradually.

Give up the mixer and continue with a goal the incorporation of flour. Finally, add the lemon peel.

For baking waffles we need a waffle maker.
Heat the appliance, grease it with butter on both the bottom and the top.
Add a polish of the composition and stretch to near the edge, then turn off the appliance. Leave for 4 minutes.
After 4 minutes the waffles are cooked and ready.
Remove with a spatula and adjust the edges.