Preheat the oven to 350 degrees. For best results, use a quality 9x13 baking dish or casserole.
Peel and then thinly slice the peaches and place in a greased shallow dish. I prefer a 9x13 casserole dish.
After you cut the peaches, layer them into the dish and squeeze a little lemon juice over each layer. This will keep the peaches from browning.
Sprinkle the granulated sugar, 1 tsp cinnamon and 1/2 tsp nutmeg over the peaches and gently toss.
In a separate bowl combine the butter, brown sugar, flour and the remaining cinnamon and nutmeg. Using a fork or pastry blender combine the ingredients into the bowl. Mix the ingredients until the butter reduces to about pea sized pieces.
Next fold in the quick oats into the bowl. Use more oats than flour for a crispy, crunchy topping.
Sprinkle the mixture evenly over the peaches.
Bake at 350 degrees for 35-50 minutes depending on the size of your baking dish, until golden brown and the peaches are soft.
Remove from the oven and let cool for 5-10 minutes before dishing out. Serve with a scoop of vanilla ice cream or whipped cream.
Notes
You can make this crumble with apples, pears, mangos, or other stone fruits. The key is the crunchy oat topping paired with soft fruit.