Instructions

1. Cut the butter into cubes and leave it at room temperature for 10 minutes to soften.
   
2. Place the softened butter in a large bowl, add the sugar and egg, and beat with an electric mixer for 2-3 minutes.
   
3. Add the flour and lemon zest. Mix everything well with a spoon, then knead with your hands until you have a smooth, homogeneous dough.
   
4. Form the dough into a ball, wrap it in plastic wrap, and refrigerate for at least half an hour.
   
5. After half an hour, preheat the oven to 180°C/350°F (160°C/320°F for a ventilated oven).
   
6. Roll out the dough with a rolling pin until it is 5 mm (1/5 inch) thick.
   
7. Cut out shapes from the dough with cookie cutters and place them on a baking sheet lined with parchment paper.
   
8. Bake the cookies in the preheated oven for 10-12 minutes (8-10 minutes in a ventilated oven), checking them occasionally.