Grill or broil the sausage in advance. When cooled, slice it thin and set aside. Wash and drain the broccoli di rape and set it aside. In a large pot, put 10 quarts water on to boil, with 3 tablespoons coarse salt added, and immediately start preparing the sauce. Add the ziti to the pot when the water boils and cook until al dente. In a large, deep, heavy skillet with a fitted lid, heat the olive oil, add the garlic, and saute, uncovered, until golden, about 2 minutes. Add the broccoli di rape, 1/4 teaspoon salt, and pepper flakes, cover, and stream 5 minutes, stirring occasionally. Stir in the sausage. Add the butter and chicken stock, and cook over high heat, uncovered, about 3 minutes, until the liquids are slightly reduced. Add the drained pasta to the sauce and toss gently. Sprinkle on 1/2 of the cheese, toss again, serve immediately, and distribute the remaining cheese over the pasta.
Recipe courtesy of Lidia Bastianich, "La Cucina Di Lidia"