Preheat oven to 400 degrees F. Arrange the squash on a baking sheet and spray with olive oil spray, season with salt, pepper and nutmeg, and roast to tender, 30 minutes. Puree in a food processor with the stock (or mash with the stock.
Simmer the puree with the cream to thicken a bit; add half the cheese.
In a skillet heat EVOO, 2 turns of the pan, over medium heat. Add the garlic and stir for 1 to 2 minutes. Add the kale and wilt.
Cook the pasta to al dente and save a small ladleful of starchy cooking water just before draining. Toss the pasta with the puree, greens and starchy water; transfer to baking dish and top with more cheese. Cool and store.
Bring the pasta to room temperature to bake. Preheat the oven to 400 degrees F. Bake until brown and bubbly on top, 40 minutes or so from room temperature.