Start by peeling and cutting the butternut squash. Slice it in half lengthwise and remove the seeds. Then, chop the squash into small cubes.
In a large pot, bring water to a boil and cook the pasta according to the package instructions until al dente. Drain and set aside.
In a large skillet, heat the olive oil over medium heat. Add the minced garlic and cook until fragrant, about 1 minute.
Add the butternut squash cubes to the skillet and season with thyme, sage, red pepper flakes (if desired), salt, and pepper. Cook for about 10-15 minutes, or until the squash is tender and easily mashed with a fork.
Using a potato masher or fork, mash the butternut squash until it reaches a creamy consistency. For a smoother texture, you can transfer the squash to a blender or food processor and blend until smooth.
Add the cooked pasta to the skillet with the butternut squash sauce. Toss until the pasta is evenly coated with the sauce.
Serve the Butternut Squash Pasta hot, garnished with grated Parmesan cheese, fresh parsley or basil, and an extra drizzle of olive oil if desired.