*The cornstarch will thicken the filling, but I’ve made it without and it’s just as good, so feel free to omit if desired. If you like more crumble, increase the oats to 2/3 cup and butter to 8 tbsp. For all other ingredient substitutions, see notes above in this post.Preheat oven to 375 F. Grease an 8x8 pan (or double the recipe for a 9x13). If using frozen berries, thaw first. Combine berries, sweetener of choice, and optional cornstarch, then spread into the pan. Combine all remaining ingredients except butter in a mixing bowl. Cut butter into the dry ingredients with a fork or pastry cutter until small crumbles form. (If using oil, simply stir it in.) Sprinkle the crumbles evenly over the berries. Bake on the center rack 25-30 minutes or until bubbly and lightly browned. Let cool before serving, as it thickens while it cools. The crumble will also thicken overnight. Store leftovers covered in the fridge, or they can also be frozen. Serve either hot or cold. If you try the recipe, be sure to rate it below!View Nutrition Facts