Put the flour, sugar and salt in a bowl. Add the butter in flakes and the egg and knead into a crumbly dough with the dough hook of the hand mixer.
Place the dough on the worktop and quickly knead into a smooth dough with lightly floured hands. Let cool in the refrigerator for about 30 minutes before further processing. Best in cling film.
Roll out the dough, cut out biscuits and bake at 180-200 degrees for 5-12 minutes.