Poke holes in the outer shell of the squash and microwave it for about 4 minutes. This softens the shell to make it easier to cut.
Cut the squash in half the longway. If the stem end is going to be problematic, you can cut that off crosswise before cutting the squash in half.
Using a metal spoon, scoop out the seeds and stringy membrane. It's a little reminiscent of carving pumpkins.
Place each squash half cut-side down in a glass baking dish. Add 1/2 to 1 inch of water and cover the dish with plastic wrap.
Cook in the microwave for about 8 minutes, or until the squash is tender.
Remove the squash from the dish with oven mitts to protect your hands. Watch for steam. With a spoon gently scrape the flesh into a medium mixing bowl. Mash it with a potato masher or if you prefer, blend it smooth in a food processor.
If serving as a side dish, stir in the optional mix-ins and serve hot.
A 2 1/4 lb squash produces about 2 1/2 cups puree.Promptly store leftovers in an airtight container in the refrigerator, for up to 4 days. Freeze for longer storage.Nutritional values are approximate and based on 1/8 the recipe. Does not include mix-ins.To prepare a savory squash puree as a side dish: mix in 1 tbsp butter, 1 tbsp whipping cream, 1/2 tsp salt, 1/4 tsp black pepper.To prepare a sweet squash puree as a side dish: mix in 1 tbsp butter, 1 tbsp whipping cream, 1 tbsp brown sugar, 1/2 tsp salt, 1/4 tsp ground cinnamon. Adjust to taste.