Preheat oven to 180C. Line 2 large cookie trays with baking paper and set aside.
Grate lemon peel for 15 seconds on speed 8.
Add butter and sugar to TM bowl, mix for 1 minute on speed 3.
Add flour, baking powder, salt and egg. Mix for 1 minute on speed 3-4 until well incorporated.
Pipe (or spoon) 20 mounds of mixture onto prepared baking trays, ensuring you leave enough space between each to allow for spreading.
Bake for 10-12 minutes until just firm to the touch.
Allow to cool for 5 minutes then carefully transfer to a wire rack with a palette knife and allow to cool completely.