Preheat the oven to 170C/325F/Gas 3.
In a large bowl beat the egg whites until firm. Mix the sugar and the almonds gently into it. Add the amaretto liquor and fold in gently until you have a smooth paste.
Place some baking paper on a baking tray and lightly brush with butter. Using a teaspoon place small heaps of the mixture approximately 2cm/¾in apart, as they will expand while cooking. Bake for approximately 15 minutes until golden brown. Leave to cool slightly then serve or store in an air-tight container.