Preheat the oven to 400 degrees F. Heat the stock with the saffron in a small saucepan over medium heat.
Meanwhile, bring 1 1/2 cups water to a boil in a pot and season with salt. Add the cauliflower, cover and steam until tender, about 12 minutes. Drain and break into florets.
Heat the EVOO in a Dutch oven over medium-high heat. Add the sausage and crumble it into very small pieces with a potato masher or wooden spoon. Add the garlic and onions and cook for 5 minutes. Deglaze with the wine, stirring and scraping up any browned bits from the bottom of the pot with a wooden spoon. Add the bay leaf, cinnamon stick, tomatoes and saffron stock and stir to break up the tomatoes. Simmer until thickened, about 30 minutes. Discard the bay leaf and cinnamon stick and season with salt and pepper.
Meanwhile, bring a large pot of salted water to a boil. Add the pasta and cook to just shy of al dente, about 7 minutes. Reserve a ladle of the starchy cooking liquid and drain the pasta.
Return the pasta to the pot. Add the heavy cream, cauliflower, sausage sauce and
a little of the reserved cooking liquid and stir to combine. Transfer the mixture to a casserole dish and top with the cheeses and parsley. Bake until the top is browned, 35 to 40 minutes. Divide among plates.
Cook's Note: The unbaked casserole can be covered and refrigerated for a make-ahead meal. Bake as directed before serving.
Recipe courtesy of Rachael Ray