Step 1: Preheat your oven to 400°F (200°C). Toss the cubed butternut squash with olive oil, nutmeg, salt, and pepper on a large baking sheet.
Step 2: Roast the squash for 25-30 minutes, or until tender and golden brown at the edges. Flip halfway through for even cooking.
Step 3: While the squash is roasting, cook the pasta in a large pot of salted boiling water according to package directions until al dente. Reserve 1/2 cup of pasta water before draining.
Step 4: In a large skillet, melt the butter over medium heat. Once it starts to foam, add the sage leaves. Fry for 1 minute until crisp, then remove and set aside.
Step 5: Add the minced garlic to the remaining brown butter in the skillet and cook for 1 minute until fragrant.
Step 6: Take half of the roasted squash and blend it with 1/4 cup of the reserved pasta water until smooth. Add this purée to the skillet.
Step 7: Add the cooked pasta and the remaining whole roasted squash cubes to the skillet. Toss gently, adding more pasta water if needed to reach a creamy consistency.
Step 8: Stir in the Parmesan cheese and top with the crispy fried sage leaves. Serve immediately.