6 tablespoons chilled unsalted butter, cut into small pieces
1/4 cup granulated sugar
2 tablespoons all-purpose flour
1/2 teaspoon ground cinnamon
1/4 teaspoon kosher salt
8 cups peeled Fuji apple slices (about 3 1/4 pounds)
1 tablespoon fresh lemon juice
How to Make It
Preheat oven to 375°.
To prepare topping, weigh or lightly spoon 5 ounces flour into a dry measuring cup; level with a knife. Combine flour and next 3 ingredients (through salt) in a medium bowl, stirring with a whisk; stir in oats. Cut in butter with a pastry blender or 2 knives until crumbly. Cover and chill 20 minutes.
To prepare filling, combine 1/4 cup sugar and next 3 ingredients (through salt) in a large bowl, stirring with a whisk. Add apple, and drizzle with lemon juice; toss well. Spoon apple mixture into an 8-inch square glass or ceramic baking dish coated with cooking spray. Sprinkle topping over filling.
Bake at 375° for 45 minutes or until apples are tender and topping is crisp. Let stand at least 15 minutes before serving.