Deep-Dish Pizza with Italian Sausage and Broccoli Rabe

For the filling: Bring a large pot of salted water to a boil, add the broccoli rabe and blanch for 2 minutes. Drain in a colander and run cold water over. Drain well again and squeeze out excess liquid. Heat 2 tablespoons of the oil, chili flakes and garlic in a large saute pan over medium heat and cook for 1 minute. Add the broccoli rabe, salt and pepper and cook until slightly tender, about 5 minutes. In a separate large saute pan, heat the remaining 2 tablespoons of oil over high heat until the oil begins to shimmer. Add the sausage links and using a wooden spoon, gently break up the meat into coarse pieces. Cook until deep golden brown. (You do not need to cook all the way because it will continue to cook in the oven.) Combine the sausage and the broccoli rabe and let cool slightly.