Preheat the oven to 400°F (200°C).

Cut the butternut squash in half lengthwise, deseed it, and dice it into small cubes. Toss with olive oil, salt, and pepper, then spread on a baking sheet.

Roast the squash in the oven for about 25-30 minutes or until tender and caramelized, stirring halfway through.

While the squash is roasting, bring a large pot of salted water to a boil. Cook the pasta according to package instructions until al dente. Reserve about ½ cup of the pasta water before draining.

In a large skillet, melt the butter over medium heat. Add the sage leaves and sauté until the butter turns golden brown and the sage becomes crispy, about 3-4 minutes. If using garlic, add it now and sauté for another minute.

Once the butternut squash is done roasting, add it to the skillet with the brown butter sauce. Toss in the drained pasta along with the reserved pasta water. Stir everything together until well coated.

Remove from heat and fold in the grated Parmesan. Season with additional salt and pepper to taste.

Serve immediately, garnished with more Parmesan cheese and sage if desired.