Heat oven to 375 degrees.
Mix the blueberries, peaches, pure maple syrup, vanilla, and cornstarch in a large bowl. Set aside.
IIn a separate medium bowl, whisk together the oat flour, coconut sugar, rolled oats, sliced almonds, cinnamon, and salt.
Using a pastry cutter or two knives, cut the butter into the oat mixture. I use my hands to work it all together. The result should be a crumb mixture that is “crumbly” and has small and medium pea shapes. This step can take 1-2 minutes.
Pour the fruit mixture into an 8 or 9-inch square baking dish sprayed with cooking spray. Evenly top with the crumb mixture—Bake for 45 minutes. The fruit should be bubbly, and the crumble should be brown. If the crumble starts to brown too quickly and seems like it may burn before the fruit cooks, then loosely place a foil over the crumble and finish cooking.
Serve warm with ice cream or frozen yogurt. This blueberry peach crisp is also tasty at room temperature.