Amaretti are traditionally from Saronno, in Lombardy, and as the word says are amari - bitter -
like most names of food in the Italian language which really describe what the food is. In this case what gives that bitterness is almonds which are the main ingredient.
I quite like the romantic legend behind them. Legend wants that in the early 18th century a Milanese bishop visited Saronno out of the blue, without having been announced. A young couple welcomed him by offering the best they could which was in that moment biscuits made with crushed apricot kernels, sugar and egg whites. The bishop was so pleased that he gave them a long lasting blessing for their marriage and advised them to preserve the recipe as a family secret.
The recipe is no secret but indeed very easy - what is tricky though is the right ratio. Here it is:
For 20 amaretti
150g ground almonds
2 egg whites - medium eggs
100g caster sugar
zest of half a lemon
a quarter of vanilla bean
Grate the lemon and scrape the vanilla bean out. Mix well with the ground almonds and sugar.
Beat the egg whites until they have a meringue look and then fold it in the almond mixture. You will have a soft mixture which you can mould into walnut size balls. Roll them in icing sugar and place them on a baking paper.
Cook in the oven at 170C for 12 minutes.