01 - Preheat oven to 350°F. Lightly grease a 2-quart baking dish with butter or cooking spray.
02 - In a large mixing bowl, combine peach slices, granulated sugar, flour, cinnamon, nutmeg, lemon juice, and salt. Toss thoroughly until peaches are evenly coated with the spice mixture. Transfer to prepared baking dish and spread evenly.
03 - In a separate bowl, whisk together flour, oats, brown sugar, cinnamon, and salt. Add cold cubed butter and work into dry ingredients using fingers or pastry cutter until mixture resembles coarse crumbs with some pea-sized pieces remaining.
04 - Sprinkle crumble topping evenly over peach filling. Bake for 35 minutes until topping is golden brown and fruit filling is bubbling around edges.
05 - Let crumble rest for 10 minutes to allow filling to set slightly. Serve warm with vanilla ice cream or whipped cream.