Cover a baking sheet with aluminum foil (the squash is full of sugar, and you don't want it burning onto your tray, that would be a mess.) Place the squash on the tray and cut a couple of slits into it with a sharp knife (be careful, the squash are very hard.)
Bake at 350 degrees until a knife can be easily inserted into the "neck" of the squash (about 60-90 minutes, depending on the size of the squash.)
Look at the sugar running out of slits that were cut into it. Cut the squash in half lengthwise to allow some of the heat to escape ('cause it will be HOT HOT HOT).
When cool enough to handle, scoop out the seeds and fibers with a spoon. Peel away the skin. Cube it up and place in a large bowl. Season with salt, cinnamon, and brown sugar, and mash with a couple of tablespoons of butter. Serve immediately, or place in a buttered casserole, cover and place in oven to reheat.