Preheat oven to 375F. Rinse peaches and blueberries. Cut peaches into bite sized cubes. You can either remove the peach skin of leave it on.
Mix the fruit with the sugar, cornstarch, and mint in a mixing bowl. Pour it into a 10 inch cast iron or a greased pie plate.
Mix the topping in a separate bowl (it should be crumbly but not dry!) and sprinkle it all over the top of the fruit mixture.
Place crisp in the oven and bake for 30 minutes at 375F.
Allow to cool slightly and serve with a scoop of vanilla ice cream!
Notes
Make this recipe gluten free by using an all purpose gluten free flour, gluten free rolled oats and check to make sure the arrowroot starch is gluten free