Bring a large pot of water to a boil, salt it, and plunge the kale or other greens in, just till they turn bright green. Fish the greens out with tongs and drain, then cook the pasta in the water until it is how you like it. Drain and save about 1/2 cup of the cooking water. Meanwhile, saute the onions and garlic in the olive oil, add the hot pepper flakes, and white wine, and let most of the wine boil off. Add the half & half, and boil that down till thickened. Add the sausage, and chop the greens and add them too. Finally throw in the pasta and parmesan, and toss well. Thin with reserved pasta waster if it seems to need it. Serve with extra cheese.