While this is a great recipe to use up some of your bounties during blueberry season, you can use frozen blueberries or any frozen fruit in any fruit crisp or crumble recipe! Use the same amount of frozen as you would fresh fruit. The freezing process breaks down the fruit's cell wall, making it softer and juicier when it thaws. Accordingly, add another 1/4 – 1/2 tablespoon of cornstarch when you sprinkle it over the frozen fruit.