Preheat oven to 400 degrees F.
On a large baking sheet, spread out the gnocchi, sausage, butternut squash, onion and brussel sprouts. Drizzle with olive oil, chopped garlic, salt and pepper and toss. Sprinkle with fresh sage.
Bake in the oven for about 20-25 minutes, flipping occasionally so it can roast evenly.
Remove from the oven after 20-25 minutes and add the fresh baby spinach to the sheet pan. Sprinkle with shredded gruyere cheese.
Place back in the oven and broil for 5-10 minutes until the spinach is wilted and everything is golden brown.
Remove from the oven and serve. Top with additional shredded cheese.