While oven is preheating, cut the squash in half. Remove the seeds and pulp from the center. Brush the olive oil over the cut side, sprinkle with salt and pepper, and lay on a parchment-lined baking sheet cut side down. Bake for 60 minutes.
Meanwhile, heat olive oil in a saucepan over medium heat, then add the garlic. Saute garlic for one minute, then add sage. Saute for another minute then add stock. Bring to a boil and add cauliflower, then cook for 5 to 6 minutes until cauliflower is soft. Add everything to a blender and blend till smooth. Add lemon juice, cheese, salt, and pepper and blend until combined.
When squash is done, scrape the flesh with a fork so the noodles come off, and divide between 4 plates. Top with 1/4 of the sage Alfredo sauce and serve!