Pre-heat oven to 325 °F.
With a spoon, stir together icing sugar, salt, and nutmeg.
Add in the egg yolk and soft butter. Stir until combined.
Add the flour, half a cup at a time, until it is too hard to mix with a spoon.
Throw the dough onto a floured board and knead until well-combined. Add extra flour if the dough becomes oily.
Roll out to a thickness of 6 mm and cut into shapes. Place on a baking tray.
Cook for 10-12 minutes at 325 °F. If the cookies start to turn brown, you have cooked for too long.