Preheat your oven to 425°F (220°C).
On a large baking sheet lined with parchment paper, spread out the butternut squash, shallots, and garlic.
Drizzle everything with olive oil and sprinkle with salt and pepper.
Roast in the oven for 25-30 minutes until the squash is fork-tender.
While the squash is roasting, cook your pasta according to the package instructions until al dente. Drain and save ½ cup of the cooking water.
Once the squash is tender, put it in a blender with the garlic, shallots, and chicken stock. Blend until smooth.
Add the cream, nutmeg, and reserved pasta water to the blender and blend again until smooth. Adjust the seasoning if needed.
In a medium pot, keep the sauce warm over low heat. Mix a few spoonfuls of sauce with the pasta, adding more until it's as saucy as you like. Serve with pecorino cheese, herbs, and cracked black pepper.