Instructions

1. Preheat oven to 425. Wrap a 10-inch springfrom pan tightly with foil and generously coat the inside of the pan with butter.
2. Cook the spaghetti according to package directions until barely al dente. Drain pasta and set aside.
3. In a large skillet over medium-high heat, heat olive oil. Add the sausage and cook until meat is cooked through and crumbly. Transfer sausage to a paper-towel lined plate, and discard all but a tablespoon of oil. In the same skillet, add the onion and cook until onions begin to turn golden, about 10 minutes. Season with a pinch of salt, add the garlic, and stir until fragrant, about 30 seconds. Add the kale and cook until just wilted. Set aside to cool slightly.
4. In a large bowl, whisk together the eggs and milk. Stir in the mozzarella, ricotta, 1 cup Parmesan, oregano, salt, and pepper. Add the spaghetti, sausage, and onion and kale mixture. Use hands to combine, being sure that spaghetti is evenly coated with the cheeses and the meat and vegetables are evenly distributed throughout.
5. Press mixture firmly into prepared pan and sprinkle over remaining tablespoon of Parmesan. Set pan on a large rimmed baking sheet and bake until top is golden and crusty, about 25 minutes.
6. Let set for 15 minutes. Carefully remove ring and slice into wedges to serve.