For an extra layer of flavor, brush the baked tart shells with a thin layer of melted white chocolate or a simple syrup before filling. If fresh peaches are not available, canned peaches can be used. Drain them well and pat them dry before using. To make ahead, bake the tart shells and store them in an airtight container at room temperature for up to 2 days. The whipped cream can be made up to 24 hours in advance and stored in the refrigerator. Assemble the peach cups just before serving to prevent the crust from becoming soggy.