Preheat oven to 350 degrees.
In a mixing bowl combine, apples, peaches, pears, cornstarch or arrowroot powder, sugar, maple syrup, vanilla, lemon juice and a teaspoon of cinnamon. Coat the chopped fruit well and place in a bottom of pie plate or deep glass baking dish. Set aside.
In another mixing bowl, combine the rest of the cinnamon, brown sugar, oats, flour, and butter together. Place the crumble over the top of the fruit layer. Garish with a little sea salt or for added sweetness you can use sugar. Cover the dish with foil to prohibit the crumble from browning to quickly.
Bake for 20-25 mins or until the fruit becomes softened and the filling is bubbling.
Once fruit filling is cooked removed foil for another 5 minutes to allow the crumble to brown.
Allow to cool enough before serving with ice cream or whipped topping!