Place the cauliflower, onions, wine, and water in a saucepan; cover.
Cook over medium heat until the cauliflower is just getting tender, about 7 minutes.
Transfer half the solids and all the liquid to a food processor, and purée until smooth. Set the rest aside. 
In a large skillet large enough to hold the pasta later, heat 1 tablespoon of the olive oil.
Add the garlic and cook over medium heat, stirring for 3 minutes.
Add the puréed cauliflower, cauliflower floret mix (set aside earlier), and cream.
Cook over medium-low heat for 4 minutes.
Meanwhile, bring 5 quarts of water to a boil. Add the pasta, and cook until al dente. Drain.
Toss the pasta with the sauce, and adjust the seasoning (black pepper, salt).
Sauté for 1 minute, then transfer to a heated bowl.
Toss with the Pecorino and serve.