Yes, I prefer to freeze it after it's baked and to freeze it in pieces. Although summer squash has a fair amount of water, it does okay when reheated in a conventional oven. Bake, cool completely, then cut into pieces. Place in an airtight container. Thaw in the refrigerator, then place the pieces in a baking dish and reheat in the oven. Any liquid will evaporate during the reheating process.