Beforehand the lemon zest grated. RUB the softened butter with sugar, add zest, flour, salt, carefully knead with a spoon and remove the dough in the fridge for an hour After an hour preheat the oven to 180*. Protiven grease with butter. The dough to get it and as soon as possible (until it warmed up to room temperature) to roll the "sausages". Bake until Golden state. While cookies are still hot, sprinkle with powdered sugar.