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 of the butternut squash, being careful to leave ½-inch border. Add the flesh to the mixing bowl.
Drain off the water from the baking dish and place the slightly hollowed butternut squash half into a baking dish. Sprinkle the flesh with ¼ teaspoon of kosher salt.
Add the butter, ½ teaspoon kosher salt, pepper, and ¼ cup of parmesan cheese into the mixing bowl with the flesh of the squash. Mix well, until butter has melted into the warm squash and the squash is nice and mashed up.
Scoop the squash mixture into the hollowed out half of the 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.
Serve warm from the baking dish or transfer to a platter to serve.
Notes
Leftovers: Store leftover baked squash in an airtight container for up to 4 days in the refrigerator. Dietary Modifications: Omit the Parmesan cheese and use vegan butter for a dairy-free version of this recipe. Preparing in Advance: Bake the squash up to 2 days before serving. Scoop out the flesh of the squash, mix the warm filling with the butter, cheese, and seasonings and restuff the squash. Place the stuffed squash in a baking dish and cover tightly with plastic wrap. Store in the refrigerator for up to 48 hours before baking again. To bake before serving, remove from the fridge, and uncover. Bake at 375 degrees for 30-35 minutes or until warmed through.