• Olive oil for the baking sheet pan and lasagne sheets
• 1 ½ pounds sweet or hot Italian sausage, casings removed, or ground round beef (85% lean)
• 5 fresh lasagne sheets
• About 7 cups pomodoro sauce
• 2 cups (8 ounces) freshly grated Romano cheese, plus more for serving
• 1 pound (4 cups) shredded part-skim mozzarella
• 1 ½ pounds whole milk or part-skim ricotta cheese
• Fine chopped fresh flat-leaf parsley for serving
1. Preheat the oven to 350 degrees. Lightly oil a 13-by-9-inch baking pan.
2. Cook the sausage in a large skillet over medium heat, breaking up the sausage well with the side of a spoon, until cooked through, about 10 minutes. Using a slotted spoon, transfer the sausage to a bowl, discarding the fat in the skillet. Set aside.
3. Bring a large pot of water to a boil over high heat. Add salt to taste. Trim the lasagne sheets to fit the baking pan, if necessary. Add the lasagne sheets, one at a time, stirring gently to keep the sheets from sticking to each other. Cook just until al dente, about 2 minutes (the water does not have to return to a boil). Drain and rinse under cold running water. Separate and toss the lasagne sheets with 2 tablespoons of oil to discourage sticking.
4. Set aside ½ cup of Romano cheese for the topping. Spread ¾ cup of the sauce on the bottom of the baking dish. Top with 1 lasagne sheet. Sprinkle with one-quarter each of the mozzarella, Parmesan, and sausage, dot with one-quarter of the ricotta, and top with ¾ cup of pomodoro sauce. Repeat three times with 3 more sheets, the mozzarella, Parmesan, sausage, ricotta, and pomodoro sauce. Top with the final lasagne sheet, 1 cup Pomodoro sauce, and the reserved Parmesan cheese. Cover loosely with aluminum foil. Reserve the remaining pomodoro sauce. (The lasagne and sauce can be prepared, covered, and refrigerated, up to 1 day ahead.)
5. Put the baking dish on a rimmed baking sheet. Bake for 45 minutes. Uncover and bake until the lasagna is bubbling, about 30 minutes more. Let stand for 15 minutes before serving.
6. To serve, reheat the remaining pomodoro sauce. Cut the lasagna into 9 portions. Transfer each to a dinner plate, top with pomodoro sauce, and sprinkle with Romano and parsley.