I like to make this in the summer when I have lots of ripe nectarines and the blueberries are at their best. My favorite part is the crust, which is light, sweet, and crunchy, and tastes just incredible with the mascarpone, an Italian stand-in for the more expected whipped cream or vanilla ice cream. Make the filling with any of your favorite fruits.
Topping:Stir the flour and sugars in a medium bowl to blend.
Add the butter and rub between your fingertips until moist clumps form.
Mix in the amaretti crumbs and almonds.
Filling:Preheat the oven to 350°F.
Butter a 13 X 9 X 2-inch glass baking dish.
Stir the sugar and flour in a large bowl.
Add the nectarines and blueberries, and toss to combine.
Stir in the liqueur.
Assembling:Spoon the fruit mixture into the prepared dish.
Sprinkle the cookie topping over.
Bake until the nectarines are tender and the topping is golden and crisp, about 45 minutes.
Cool for at least 10 minutes.
Spoon the warm crisp into bowls.
Top each with a dollop of mascarpone cheese and serve.