Step 1

Heat oven to 425 F.

Step 2

Bring 4 quarts of water to a boil. Add 2 tablespoons salt and tortellini; cook until just shy of al dente according to package directions – about 30 seconds less than the recommended cook time for fresh, fast-cooking tortellini; 1 to 2 minutes shy for frozen varieties. Drain the tortellini and set aside.

Step 3

Meanwhile, in a 12- or 14-inch ovenproof skillet, warm olive oil over medium heat. Add onion and a few pinches of salt and pepper. Cook for 4 to 6 minutes, or until the onion is mostly tender.

Step 4

Crumble sausage into skillet, using a spoon to break it into small pieces. Cook until starting to brown, stirring occasionally, about 5 minutes. Stir in garlic and cook 1 to 2 minutes longer. Add red wine vinegar. Cook, stirring constantly, until it has evaporated, about 30 seconds.

Step 5

Stir in marinara. Lower heat and let simmer for 5 minutes to marry the flavors. Add the cooked tortellini, gently stirring to fully coat in the sauce. Take the skillet off the heat.

Step 6

In a small bowl, stir together ricotta and mozzarella with 2 tablespoons of cream or milk to thin. (You’re looking for a smooth, spreadable consistency.) Season with salt and pepper. Dollop the ricotta mixture evenly over the pasta, then top with remaining mozzarella and Parmesan.

Step 7

Bake for about 15 minutes, or until the sauce is bubbling around the edges and the cheese is melted and lightly browned. Serve warm.