Preheat oven to 350 degrees Fahrenheit. Place rack in center of oven.
Cut a peach in half and take out the pit. Scoop out some flesh so that there is room for the topping.
In a bowl, whisk together flour, brown sugar, gluten-free certified oats, cinnamon, nutmeg, ginger, and salt.
Add the butter to the topping mixture and mix with a fork until the butter is the size of peas.
Place the peach halves into an oven-safe 9x13-inch baking dish. Stuff the crumble topping into the peach halves.
Bake at 350F for 22-25 minutes.
Serve warm with a scoop of ice cream.