Wash and dry the butternut squash. Cut off the stem of the squash and then cut the squash in half lengthwise. Remove the seeds from the cavity of the squash.
Place the two halves of the squash, cut side down, in a large baking dish. Pour 2-3 cups of cold water into the baking dish, or until the water comes halfway up the sides of the squash.
Bake the squash for 45 minutes, or until the flesh is fork-tender. Once tender, remove the squash from the oven and let cool for 10 minutes, just until you can handle it.
Using a spoon, scoop out the flesh of one half of the squash and place it into a large mixing bowl. For the remaining half, carefully scoop out a portion of flesh, adding it to the bowl, but leave ½-inch border of the squash intact. Place the hollowed out squash cavity into a baking dish and sprinkle with ½ teaspoon kosher salt. (Feel free to use same baking dish as before, just drain off the water.)
To the mixing bowl with the flesh of the squash, add 2 tablespoons of butter, ½ teaspoon kosher salt, ½ teaspoon pepper, and ¼ cup of parmesan cheese. Mix well, until butter has melted into the warm squash and the squash is nice and mashed up.
Scoop the mashed seasoned squash mixture into the hollowed out half of the butternut squash. Sprinkle the filling with the remaining ¼ cup of parmesan cheese.
Return the stuffed squash to the oven and bake for 15-20 minutes, or until the cheese is melted and the filling is warmed through.
Notes
Make-Ahead Instructions: You can assemble this stuffed butternut squash up to baking the second time up to 48 hours in advance. Once assembled, place the stuffed squash into an airtight container and refrigerate for up to 48 hours. When ready to bake, remove the stuffed squash from the refrigerator, place on a baking sheet or casserole dish, and bake at 350 degrees F for 45-50 minutes. Storage: Store leftover baked squash in an airtight container up to 4 days in the refrigerator. Reheat in the microwave on a heat-safe plate until warmed through.Maple Cinnamon Twice Baked Squash: Mash the flesh of the baked butternut squash with 1 teaspoon of ground cinnamon or pumpkin pie spice, 2 tablespoons unsalted butter, ½ teaspoon kosher salt, and ¼ cup maple syrup (or brown sugar.) Stuff the squash cavity as directed. Top with chopped pecans or walnuts if desired and bake as directed for the second time. Add Additional Flavor: Add up to 1 teaspoon each of onion powder, garlic powder, and/or smoked paprika for additional flavor that will pair well with the butter and parmesan cheese.Dairy-Free Modification: Replace the butter with extra virgin olive oil and omit the parmesan cheese.