Grind 100 g of walnuts, then mix with flour and sugar. Add the butter pieces and amaretto, chop everything through with a knife and then knead quickly with your hands until smooth.
Shape the dough into walnut-sized balls and place them on a baking tray lined with baking paper. Place half a walnut on each ball and press on.
Bake in the preheated oven at 175 degrees, convection 160 degrees for about 15 minutes. Dust with powdered sugar.