Preheat your oven to 400°F. Cut the butternut squash in half lengthwise and scoop out the seeds. Brush the cut sides with olive oil, season with a little salt, and place the squash cut-side down on a baking sheet. Roast for 45-50 minutes, or until the flesh is very tender.
Scoop the roasted squash into a blender. Add the garlic, butter, chicken stock, ground sage, dried thyme, and salt, then blend until smooth and creamy. If needed, add a little more chicken stock, a splash at a time, until the purée blends easily. Set aside.
Heat a large skillet over medium-high heat. Add the sliced chicken sausage in an even layer and cook for a few minutes per side until nicely browned.
Reduce the heat to medium-low, then add the cauliflower gnocchi, half and half, and chicken stock. Stir gently, cover with a lid, and let simmer for about 5 minutes, or until the gnocchi is tender.
Stir in about 2 cups of the butternut squash purée and the Parmesan cheese until everything is well coated.
If you'd like a thinner sauce, gradually stir in additional chicken stock until it reaches your desired consistency. I like mine thick and creamy, so I usually add about another ½ cup.
Finish with a generous sprinkle of grated Parmesan before serving.