You can use a myriad of fruits for this crisp. Think of fruits that are in season together for some great combinations; strawberries, rhubarb, and cherries in early summer, peaches, plums, nectarines and blueberries at summer’s height, and apples and pears in the fall and winter. Fresh berries and cherries work best when they’re used in combination with other fruit, as they can get too mushy on their own.