How to Make It
Preheat oven to 375°F. Lightly coat a 9-inch springform pan with cooking spray. Set aside.
Cook sausage in a medium saucepan over medium-high, stirring often, until meat is browned and crumbled, about 10 minutes. Add tomato paste, and cook, stirring constantly, until dark brown, about 1 minute. Add red wine, and cook until wine has been absorbed, about 1 minute. Stir in tomatoes, onion, and olive oil. Bring to a boil; reduce heat to medium-low, and simmer until onion is very soft, 55 minutes to 1 hour. Discard onion (or reserve for another use), and stir in salt and pepper. Set aside.
Bring 2 large pots of salted water to a boil, and fill a large bowl halfway with ice water. Add pasta to 1 pot of boiling water, and cook until not quite al dente, 5 to 6 minutes. Drain, reserving 1/2 cup cooking water. Add pasta and reserved cooking water to sauce, and toss well to coat.
Add broccoli rabe to second pot of boiling water, and cook until bright green and tender, 1 to 2 minutes. Drain and plunge into prepared ice water. Remove from ice water, and drain on paper towels. Reserve 3 spears. Chop florets from stems of remaining broccoli rabe; chop stems into 1-inch pieces. Stir chopped broccoli rabe and florets into pasta mixture.
Spread about one-third of pasta mixture in an even layer in prepared pan, making sure bottom is completely covered. Sprinkle with 1 cup of the fontina cheese. Repeat layers 2 more times.
Sprinkle top with remaining 1/2 cup fontina. Sprinkle with pecorino Romano, and top with reserved broccoli rabe spears.
Bake in preheated oven until top is golden and interior is heated through, 25 to 30 minutes. Cool in pan 10 minutes; remove sides of pan. Cut into 8 wedges, and serve.