1-Preheat and prep: Preheat oven to 375°F (190°C). Grease an 8×8 inch baking dish and place it on a rimmed baking sheet.

2-Prepare the filling: In a large bowl, combine 6 cups sliced peaches, 1/2 cup sugar, 1 tablespoon lemon juice, 2 tablespoons cornstarch, and 1 teaspoon cinnamon. Stir gently and pour into the prepared dish.

3-Make the topping: Whisk 1 cup flour, 1 cup rolled oats, 1/2 cup brown sugar, 1/4 cup granulated sugar, 1 teaspoon cinnamon, 1/2 teaspoon nutmeg, and 1/4 teaspoon salt. Cut in cold butter pieces until crumbly.

4-Assemble: Sprinkle the crumble topping evenly over the peaches. Do not press it down.

5-Bake: Bake for 35 to 45 minutes, until the filling is thick and bubbly and the topping is golden brown. Tent loosely with foil if browning too quickly.

6-Rest and serve: Cool on a wire rack for at least 15 to 20 minutes. Serve warm with vanilla ice cream or heavy cream.