I made the following dessert during my Crisps & Cobblers cooking class, which you can read about HERE.

1/4 cup all-purpose flour
1/4 cup unsalted butter
1/4 cup rolled oats
3/4 cup packed light brown sugar
1/2 cup chopped pecans or walnuts
3/4 teaspoon ground cinnamon
1/2 teaspoon freshly grated nutmeg

FILLING:
1 1/2 pounds raspberries
1/2 pound peeled, thinly sliced nectarines
1/4 teaspoon ground ginger, or to taste
1/3 cup sugar, or to taste
2 teaspoons cornstarch

Preheat the oven to 350 degrees.
Butter a 10 by 8-inch casserole dish.

Prepare the topping: In a food processor, pulse the flour and butter until the texture of coarse cornmeal. Remove to a bowl and toss with remaining ingredients until mixed.

Prepare fruit filling: Combine all ingredients in a bowl and mix well.

To assemble: Place the fruit filling in the buttered dish. Cover the filling with a 3/4-inch layer (or more) of the topping.

Bake until bubbling and the fruit in the middle is tender, 25 to 30 minutes.
Serve warm for best flavor or with ice cream, if desired.