Preheat the oven to 425° F. In a medium bowl, mix together the milk, spinach, sage, thyme, fontina, and mozzarella. Season with red pepper flakes, salt, and pepper.Place the squash in a baking dish and season the cut sides with salt and pepper. Sprinkle 1/2 of the provolone cheese into the bottom of each squash, then evenly divide the milk/cheese mix among the squash cavities. Top with the remaining provolone and parmesan. Cover the squash with foil. Slice off the top portion of the garlic head to expose some of the cloves. Place the garlic on a piece of foil. Drizzle with olive oil and wrap it up. Bake the squash and garlic for 30 minutes. Remove the foil from both and continue baking the squash and garlic another 15-20 minutes or until the squash is tender and the cheese is golden brown on top.Let the garlic cool, then squeeze the cloves out into a bowl. Add the butter and 1 tablespoon sage. Mash the cloves into the butter with a fork. Spread the butter over the squash, then use a fork to scrape the squash into strands, mixing the cheese with the squash. Enjoy!