- Preheat oven to 375 degrees F
- In a bowl, mix together peach filling: peaches, maple sugar, lemon juice, corn starch, salt, and cinnamon. Place mixture in a small (8 or 9-inch) round, square, or rectangular baking dish.
- In a separate bowl, mix together crumble topping: flour, maple sugar, walnuts, oats, cinnamon, salt, and butter. Using your hands, make sure the butter is incorporated well into the mixture. Place crumble topping on top of the peach filling in the baking dish.
- Bake 30 minutes till bubbling and golden brown.