1. Preheat your oven to 425 degrees F.
2. Place the squash on a plate and microwave it for about 3 minutes. Allow it to cool slightly, then cut in half lengthwise, scoop out the seeds, and discard. Season the cut sides with salt and pepper.
3. Transfer the squash halves to a baking dish, cut side up. Bake for 30 to 35 minutes, or until tender.
4. Meanwhile, heat 6 tablespoons of butter in a large skillet over medium heat. Add the walnuts and sage, cooking for about 5 minutes until toasted. Remove the walnuts and set aside.
5. In the same skillet, add the remaining butter and minced garlic. Sauté for about 2 minutes until fragrant.
6. Add the crushed red pepper flakes, milk, goat cheese, manchego, and pesto. Season and stir until smooth and creamy.
7. When the squash is ready, scrape the strands into a bowl and toss with the creamy sauce.
8. Serve warm, topped with the buttery walnuts.
