Store the roasted squash in an airtight glass container in the refrigerator for up to 4 days. You can freeze it for up to 3 months by spreading portions into freezer bags and removing excess air before sealing. Thaw frozen squash overnight in the refrigerator before reheating. Reheat the squash at 400°F for 10 to 15 minutes until the edges warm and regain some roasted texture. Add a teaspoon of olive oil and fresh thyme after reheating if the surface looks dry. Discard leftovers that develop a sour smell, slimy texture or unusual discoloration.