Preheat your oven to 400°F (200°C) and prepare a baking sheet with parchment paper.

Cut the butternut squash in half lengthwise, scoop out the seeds, and dice it into 1-inch cubes. Toss with olive oil, salt, and pepper, then roast for 25-30 minutes.

While the squash roasts, bring a large pot of salted water to a boil and cook your pasta until al dente, reserving about 1 cup of pasta water.

In a large skillet, heat olive oil and sauté chopped onion until translucent. Add minced garlic, chopped sage, and red pepper flakes, and cook until fragrant.

Transfer roasted squash to a blender with sautéed aromatics, vegetable broth, and heavy cream or coconut milk. Blend until smooth, adding reserved pasta water for desired consistency.

Toss the drained pasta with the creamy butternut squash sauce in the skillet, adjusting seasoning with salt and pepper.

Plate the pasta and garnish with toasted walnuts and fresh sage leaves. Optionally drizzle with extra olive oil and sprinkle with Parmesan cheese.