1. Put all the ingredients except for the butter and the milk in a mixer. Mix on high speed for a couple of minutes.
2. Add the butter in stages and then add the milk. When the dough is homogenous, stop and take it out. Keep in the fridge for an hour.
3. Create a long cylinder out of the dough with a diameter of 2-3 centimetres. Roll in sesame seeds or poppy seeds.
4. Cut half-centimetre slices of the cylinder, place onto a greased baking mould and bake for 20 minutes at 200ºC or until golden.
5. The biscuits keep well in a sealed jar.