For an extra layer of flavor, toast the oats and wheat germ in a dry skillet over medium heat for a few minutes before adding them to the topping mixture. Feel free to experiment with other fruits, such as cranberries, peaches, or plums, depending on the season and your preferences. If you don't have pumpkin pie spice, you can create your own blend using cinnamon, ginger, nutmeg, and allspice. The crisp can be prepared ahead of time and baked just before serving. Store the unbaked crisp in the refrigerator for up to 24 hours.