Whisk egg whites to form medium peaks
Mix the sugar and ground almonds together in a separate bowl and carefully fold into the egg whites
Add the vanilla and amaretto and fold in gently to to make a paste.
Cut the roll into small sections and shape into oval or round balls. Flatten each ball slightly and leave to air for at least an hour until a shell has formed.
Dust each biscuit in powdered sugar. Bake in the oven for 15 minutes.