1. Preheat the oven to 350°F.
2. Toss the apples, strawberries, blueberries, sweetener, cinnamon, and orange juice together in a mixing bowl.
3. Pour the apple mixture into a baking dish or four individual custard cups.
4. In the now empty mixing bowl, combine the rolled oats and margarine, then sprinkle it over the apple mixture.
5. Place the baking dish in the hot oven to bake for 40 to 45 minutes or 20 to 25 minutes for the individual cups.
6. After that time, the crisp should be golden brown and bubbling, remove it from the oven, let it cool for 3 to 5 minutes, and then serve with the frozen low-fat vanilla yogurt!
