A popular favorite in the fall, butternut squash tastes great when roasted, mashed or pureed into a soup. It has a a light, almond-colored rind and bright orange flesh with a nutty, buttery flavor. While the thick rind allows you to store butternut squash sometimes for several months, freezing lets you preserve an abundance of squash for later use in recipes. Blanch or cook the butternut squash before freezing to stop the enzyme action that contributes to maturation -- these enzymes may remain active while frozen and can toughen the squash and deplete its flavors.
Wash the squash skin thoroughly to remove all the dirt. Peel off the skin with a knife or vegetable peeler.
Cut the squash in half lengthwise. Scoop out the seeds and pulp. Cut the orange flesh into 1-inch cubes.
Blanch, steam, roast or cook the squash pieces in a microwave oven until soft. To blanch squash, you can boil it in water for only about 3 minutes to soften. Steam blanching takes about 10 minutes, but none of the flavor is lost in the water as can happen with submerged blanching. To roast the squash, drizzle the pieces with a light coating of olive oil and roast at 350 degrees Fahrenheit for about 20 minutes. Microwave ovens vary, but it generally takes five to 10 minutes to soften butternut squash this way.
Drop the cubes into a bowl of cool water for a few minutes to cool the squash and stop the cooking process.
Mash the squash cubes with a potato masher or fork, if desired. Alternatively, you can freeze the cubes whole.
Fill ice cube trays, muffin pans or similar trays with mashed butternut squash. Spread whole cubes evenly on a baking tray with space between each cube. Place the tray in the freezer for about 1 hour or until the cubes are frozen solid.
Remove the frozen squash from the trays and place it in a plastic freezer bag or similar freezer-safe container. Leave about 1/2 inch of empty space at the top of the bag.
Seal the bag tightly and remove as much air as possible. Squeeze out the air as best you can. Close the bag almost entirely, leaving about 1 inch open; insert a straw in the hole and suck out excess air. The straw method is optional, but helps to remove the last bit of air to extend the food's freezer life.
Label the bags clearly with a permanent marker. Write "butternut squash" and the date on each bag. Place the bags in the freezer and store for eight to 12 months.