01 - Preheat the oven to 350°F. Lightly grease a 2-quart baking dish with butter or cooking spray.
02 - In a large bowl, combine peach slices, granulated sugar, flour, cinnamon, nutmeg, lemon juice, and salt. Toss until peaches are evenly coated. Pour mixture into the prepared baking dish.
03 - In a separate bowl, whisk together flour, oats, brown sugar, cinnamon, and salt. Add cold cubed butter and blend using your fingers or a pastry cutter until mixture forms coarse, pea-sized crumbs.
04 - Evenly sprinkle crumble mixture over peaches, covering completely. Bake for 35 minutes until topping is golden brown and fruit filling is bubbling around edges.
05 - Let crumble rest for 10 minutes before serving. Serve warm with vanilla ice cream or whipped cream if desired.