Crush the amaretti with a rolling pin, leaving them in the paper wrappings as you do so. Leave plenty of texture in the crumbs rather than reducing them to a powder. Combine the amaretti, flour, sugar, cinnamon, and salt in a bowl. Cut the butter into small pieces; then work it into the dry ingredients with 2 knives or your fingertips, until the texture is crumbly and beginning to hold together.

Preheat the oven to 400° F. Peel the fruit and slice it thinly. Toss it with the sugar and lemon juice; then lay it in a 9-or-10-inch pie plate, or similarly sized earthenware or porcelain gratin dish. Cover the fruit with the crisp topping, and bake it for 30 minutes, or until the top is nicely browned and the apples are cooked. Serve with cream whisked just enough to thicken it slightly, and flavored, if you like, with amaretto.