This dish is really best eaten the same day you make it. You can refrigerate leftovers for a couple of days, but as soon as they have been in the refrigerator for a couple of hours, the breadcrumb mixture will start to absorb water and soften. When you’re ready to eat, I highly recommend reheating in the oven instead of the microwave to bring back some of the crunch. As for freezing, I don’t recommend that at all. Tomatoes just don’t take well to freezing and defrosting, and you’ll have a similar issue with the topping becoming soggy.