Put the flour, potato starch, sugar and eggs in a bowl, then heat the butter in a saucepan and when it has softened add it to the bowl.

Add also the vanilla extract, a pinch of salt and mix well, then grate the lemon peel and add it to the rest of the dough. Add the baking powder and mix everything together.

Moisten your hands with a little water and create many little balls that you will put on a plate. In the meantime, start heating the oil for frying in a high-sided pan, calculating a spoonful of oil for each frittella. Check the temperature of the oil with a toothpick, if the oil starts to sizzle on the toothpick it will be the right temperature for frying.

Fry two or three frittelle at a time, so that they don’t lower the temperature of the oil excessively. Remove them when they are golden brown and let them rest on a paper towel. Once cooled, sprinkle with icing sugar.