old classic ...
- Preheat the oven to 190 C - 375 F. Knead the butter with the sugar and add one egg at a time, stirring until a fine foamy mass is obtained. Add vanilla and lemon zest. Add flour and stir with a wooden spoon until the mixture is well combined. Leave in the fridge for half an hour.
- Coat the molds with butter or spray with oil and fill with the mixture. Bake for 15-20 minutes. Sprinkle with powdered sugar, cool completely on a wire rack and store in a metal box. They can stand for a long time, with standing the taste improves.