Bring a large pot of salted water to a boil. Add the broccoli rabe and boil for 2-3 minutes until just wilted. Remove the broccoli rabe from the pot and immediately plunge into a bowl of ice water. Drain and set aside.
Cook the pasta in a the same pot of boiling salted water until al dente, about 9-10 minutes, drain and set aside.
Meanwhile, heat the oil in a large skillet over medium heat, add the sausage, onion, bell pepper, garlic and red pepper flakes and sauté for 3 minutes, stirring frequently. Add the wine and stock and cook 3-5 minutes more. Add the cooked broccoli rabe and stir well to mix. Cook another 3-4 minutes, stirring until the broccoli is tender but still crisp and the liquid has reduced by half. Season to taste with salt and pepper.
Transfer the sausage-broccoli mixture to a large serving bowl. Toss with the pasta and sprinkle generously with Parmesan cheese.