01 - Preheat your oven to 350°F. Lightly grease a 2-quart baking dish with butter or cooking spray to prevent sticking.
02 - In a large mixing bowl, combine the sliced peaches, granulated sugar, flour, cinnamon, nutmeg, lemon juice, and salt. Toss everything together until the peaches are evenly coated with the seasoning mixture.
03 - Transfer the seasoned peach mixture into your prepared baking dish, spreading it into an even layer.
04 - In a separate bowl, whisk together the flour, oats, brown sugar, cinnamon, and salt. Add the cold, cubed butter and use your fingers or a pastry cutter to work it into the dry ingredients until coarse, pea-sized crumbs form.
05 - Sprinkle the crumble mixture evenly over the peaches, covering the fruit completely.
06 - Bake for 35 minutes until the topping is golden brown and the fruit filling is bubbly around the edges.
07 - Allow the crumble to cool for at least 10 minutes before serving. This helps the filling set slightly. Serve warm with vanilla ice cream or whipped cream if desired.