01 - Preheat the oven to 350°F. Lightly grease a 2-quart baking dish with butter or cooking spray.
02 - In a large mixing bowl, combine sliced peaches, granulated sugar, flour, cinnamon, nutmeg, lemon juice, and salt. Toss gently until peaches are evenly coated. Transfer mixture to the prepared baking dish, spreading into an even layer.
03 - In a separate bowl, whisk together flour, oats, brown sugar, cinnamon, and salt. Add cold cubed butter and use your fingers or a pastry cutter to blend until the mixture forms coarse, pea-sized crumbs.
04 - Evenly sprinkle the crumble mixture over the peaches, covering completely. Bake for 35 minutes until the topping is golden brown and the fruit filling is bubbling around the edges.
05 - Remove from oven and let cool for at least 10 minutes to allow the filling to set. Serve warm with vanilla ice cream or whipped cream if desired.