Ingredients

Makes 8 servings

　　1 1/2 cups all-purpose flour

　　1 1/8 cups old-fashioned oats

　　1 1/8 cups packed light brown sugar

　　1 1/2 cup walnuts (5 ounces), toasted , cooled, and finely chopped

　　1 1/2 teaspoons cinnamon

　　3/4 teaspoons salt

　　1 1/2 sticks (3/4 cup) unsalted butter, cut into 1/2-inch cubes and softened

　　4 1/2 pounds sweet-tart apples such as Gala

　　3 tablespoons fresh lemon juice

　　4 1/2 tablespoons granulated sugar, or to taste

　　2 tablespoons all-purpose flour

　　

Accompaniment:

whipped cream or vanilla ice cream

　　

Step 1

Put oven rack in middle position and preheat oven to 375°F. Butter a 12- by 9- by 2-inch glass or ceramic baking dish (3 to 3 1/2 quarts.

　　

Step 2

Stir together flour, oats, brown sugar, walnuts, cinnamon, and salt in a bowl, then blend in butter with your fingertips until mixture forms small clumps.

　　

Step 3

Peel and core apples and cut into 1/4-inch-thick wedges, then toss with lemon juice, granulated sugar, and flour in a large bowl. Transfer to baking dish, spreading evenly.

　　

Step 4

Crumble oat topping evenly over apple mixture and bake until topping is golden and apples are tender, about 45 minutes. Cool slightly and serve warm.

　　Cooks' note:

　　Crisp can be baked 4 hours ahead and kept, covered, at room temperature. Reheat in a preheat 350°F oven until warm.