100g caster sugar (granulated sugar for my US friends)
165g ground almonds
30ml amaretto liqueur
Start by separating the egg. In a small bowl slowly whisk the sugar into the egg yolk. Next add the ground almonds and mix until combined. Then add the liqueur and mix until combined.
Try to whisk the egg white as best as you can. It's one egg white so there is a limit to how fluffy you can get it! Then mix the egg white into the almond/sugar mixture until combined. Shape the dough into a ball, wrap in cling film and leave in the fridge overnight.
After the dough has been refrigerated take it out of the cling film and break a bit off, shape it into a ball using the palm of your hands. You want the balls to be about 20g, I weigh the first one and then get the others to the same size by look and feel. No need to weigh each ball.
Place on a baking tray and bake in a preheated oven at 160c (375f) for 30 minutes. They should be golden brown when you take them out. You want a nice crust on the outside with a chewy inside. Sprinkle with icing sugar (confectioners sugar for my US friends) and serve with coffee.