1. Heat oven to 350 degrees F. Coat a 1-1/2- to 2-quart shallow baking dish with nonstick cooking spray.
2. In a large bowl, toss together apple pieces, walnuts, blueberries, brown sugar and honey. Sprinkle with tapioca, cinnamon and cloves. Stir to coat completely.
3. Pour mixture into prepared dish, spreading level. Dot with butter. Cover with aluminum foil and transfer to 350 degrees F oven.
4. Bake crisp at 350 degrees F for 30 minutes. Uncover and stir. Bake an additional 30 minutes, uncovered, until apples are tender and juices are thick and bubbling.
5. Remove dish from oven. Let stand 10 to 15 minutes. Place granola bars in a small resealable plastic bag and crush with a heavy pan or rolling pin. Sprinkle over apple mixture and serve warm with frozen yogurt, if desired.