2 9-inch pie crusts, softened
1/2 cup brown sugar
3 tablespoons all-purpose flour
2 teaspoons ground cinnamon
1 teaspoon ground nutmeg
9 cups apples, peeled and thinly sliced
For the crumb topping:
1 cup all-purpose flour
1/2 cup granulated sugar
1/4 cup quick-cooking oats
1/2 cup (1 stick) cold butter, cubed
Preheat oven to 425°F.
On a lightly floured surface, stack pie crusts on top of each other and roll out into a 12×17-inch rectangle.
Place crust into a 10×15-inch jelly roll pan, pressing into the corners. Fold any overhang down so crust is even with edges of the pan.
In a large bowl, mix together the brown sugar, flour, cinnamon, and nutmeg. Add apples and toss to coat. Spoon apples into pan, spreading evenly across the crust.
In a medium bowl, mix together the crumb topping. Stir together the flour, sugar, and oats, and add butter, cutting in with a pastry blender or two knives until crumbly. Sprinkle topping over apples.
Bake until crust and streusel are golden brown, 35-38 minutes. Let cool on wire rack 30 minutes before serving. Enjoy!