Beat the eggs, together with the lemon rubbing, the vanilla, the sugar and the pinch of salt in a mixer until creamy. In the meantime, sift and mix the flour and baking powder. When the sponge mixture is nicely whipped, fold in the flour - baking powder mixture. Using a piping bag and a 9mm nozzle, pipe round spirals of any size onto baking paper.
Bake for approx. 8 minutes (165°C convection oven). To cool the omlettes, place the baking paper on kitchen towels and sprinkle some sugar on top. Once they have cooled, you can fill them as you like.