Check the noodle package for its required sauce liquid, oven temperature and covered baking time. These directions use 375°F and oven-ready sheets that fit about 3 per layer in a 9-by-13-inch pan. Use two deep 9-by-13-by-3-inch baking dishes, each with at least a 5-quart capacity, on rimmed baking sheets. Lightly grease the dishes. If your noodle brand has a different shape, trim or break sheets to fit each layer without stacking overlaps, and buy enough for four layers in each dish.

Use a roomy 6–8-quart pot. Brown the beef, sausage and onion over medium-high heat, breaking up the meat, for about 12–18 minutes. Work in batches if necessary. Ground beef and pork sausage must reach 160°F. Drain excess fat, then stir in the salt, garlic powder, Italian seasoning, marinara and tomato sauce. Simmer gently for 15 minutes, stirring occasionally. Stir in the 1½ cups water; add any further liquid specifically required by your noodle package. The sauce should be loose and spoonable rather than a thick meat paste.

Mix the ricotta, Parmesan and dried parsley in a bowl. Reserve 2 cups of the measured mozzarella for the tops; divide the remaining mozzarella into 6 portions for the filling. Divide the ricotta mixture into 6 portions as well. Split the meat sauce evenly between the two pans’ portions before layering, so the second pan does not run short.

Build each pan the same way: spread about ¾ cup of its sauce across the bottom, then add 3 oven-ready sheets. Cover the sheets with roughly one quarter of that pan’s remaining sauce, one portion of ricotta mixture and one portion of filling mozzarella. Repeat this noodle, sauce and cheese layer twice more. Add a fourth layer of 3 sheets, cover completely with the last quarter of sauce, and finish with 1 cup reserved mozzarella. Keep every noodle edge covered with sauce and leave at least ½ inch of headroom.

Lightly grease the underside of two pieces of foil and tightly cover the pans. Bake at 375°F for about 45–60 minutes covered, or for the time and temperature required by your noodle package. If baking both together, leave space for air to circulate and swap their positions halfway through. Remove the foil and bake about 10–15 minutes more, until the cheese is melted, the sauce is bubbling and the center reaches 165°F. A thin knife should slide easily through the pasta. If the noodles are still firm, cover again and continue baking in 10-minute intervals; a cold pan can need longer.

Let the lasagna rest for 15 minutes before cutting. Slice each pan into about 8–10 portions.

To freeze an unbaked pan, first cool the cooked meat sauce promptly in shallow containers in the refrigerator, then assemble with the chilled sauce and cold cheeses. Use a freezer-to-oven metal pan, wrap it tightly, label it and freeze for up to 3 months. Thaw in the refrigerator, usually 24–48 hours for a deep pan. Bake from thawed, tightly covered, using the noodle package’s directions; allow about 65–85 minutes covered, then uncover for 10–15 minutes, and continue as needed until the noodles are tender and the center reaches 165°F. Keep the pan on a rimmed sheet. Do not move a frozen glass or ceramic dish directly into a hot oven.

Refrigerate baked leftovers in shallow portions within 2 hours, or within 1 hour above 90°F. Keep refrigerated for 3–4 days, or freeze cooled portions for up to 3 months. Reheat covered to 165°F throughout.