Butternut squash is a large variety of winter squash that can be frozen in a number of ways depending on how it will eventually be used. While it is not advisable to freeze an entire squash, freezing butternut squash in raw chunks is an easy option that enables multiple different uses after defrosting. Cooked butternut squash can generally be frozen in two different ways, either as cubes or chunks or in pureed form.
Regardless of how the squash will eventually be frozen, all butternut squash needs to be peeled and the seeds removed. Since the flesh of butternut squash is protected by a thick outer skin, a very sharp knife or vegetable peeler should be employed in the peeling process. To safely prepare a butternut squash for freezing, both ends should be removed the squash should be cut in half to facilitate navigating its irregular shape during peeling. By standing the squash on one of the now flat ends, the skin can be shaved off using either the vegetable peeler or sharp knife. After the peel is gone the seeds can be scooped out with a spoon; it is not recommended to remove the seeds before peeling because the resulting chasm will make the squash more fragile and difficult to hold steadily.
If freezing butternut squash raw is the goal, the rest of the process is fairly simple. The raw flesh can be cut into chunks or cubes in any desired size, and they are ready for the freezer. Food storage bags are a good vessel for freezing butternut squash in raw chunks because they seal tightly, and as long as all of the excess air is removed, they do a decent job of staving off freezer burn. Double wrapping the bags by covering them in plastic wrap or aluminum foil can be helpful if the bags do not seem to seal tightly enough.
Cooked chunks of butternut squash can also be frozen in food storage bags. The squash can be roasted, boiled, microwaved, or cooked in any desired way before freezing. After cooking, it is very important to let the squash cool completely before wrapping the chunks and trying to freeze them. Putting warm squash into freezer bags will cause condensation to form inside the bag, and that moisture will freeze into ice crystals and possibly compromise the texture of the squash flesh. Cooked, frozen squash can be defrosted and used in mashes, side dishes, or casseroles.
Freezing butternut squash as a puree is a good trick for making quick soups later on. After the squash is cooked, it can be pureed until smooth in a food processor. Before freezing, the butternut squash puree should be drained over a mesh strainer or cheesecloth to remove excess moisture and prevent crystallization. The strained puree can be initially frozen in ice cube trays, and then the cubes transferred to freezer bags for long-term storage. Another option for freezing butternut squash puree is to portion the squash into plastic containers, which can then be tightly sealed and labeled with the quantity and date.