Preheat oven to 400 degrees. Split squash in half and remove seeds with a sturdy spoon. Place squash cut side down in a casserole dish. Fill halfway with water and cover tightly with foil. Place squash in the oven and cook for 45-50 minutes, or until the squash is fork tender.
While squash is cooking, met butter in a large saute pan. Add pancetta and cook until browned. Add diced apples, walnuts, and maple syrup and cook until apples release their juices then reduce.
When squash is finished cooking, remove from casserole dish and turn cut side up in a baking dish or on a sheet pan. Fill the hollows of the squash with the apple mixture. Top with cheddar cheese and place back under the broiler until the cheese is melted and bubbly, about 5 minutes.
Enjoy! By the way, be bold and try eating the skin! You will be pleased to find out the water bath softens the skin so that you can eat it with no problems!