Preheat the oven to 350 degrees
Add the filling ingredients to a large mixing bowl: frozen blueberries, sugar, cornstarch, salt, and cinnamon
Stir well and let the mixture sit for 5 - 10 minutes while you make the crisp topping
Measure the coconut oil and butter while solid, then melt in the microwave until liquid
Add all ingredients for the blueberry crisp topping to a bowl and mix together with a spoon or rubber spatula
Once the blueberry filling has sat for a few minutes, stir again to make sure the blueberries are well coated in the cornstarch
Add the filling to a pie dish, or small baking dish
Spread the crisp topping evenly over the blueberries
Bake the crisp for 50 - 60 minutes, or until the blueberry filling is bubbly and the crisp topping is browned and crunchy on top
Serve hot with vanilla ice cream on top