• Set the oven to 400 degrees Fahrenheit.
• Place the oven rack in the center. for 20 minutes, soak the lasagna noodles in hot tap water.
• In the meantime, prepare your sauce and dry them with paper towels.

TO MAKE THE SAUCE:

• In a big pan with olive oil already heated, add chopped onion. Cook until transparent over low heat (about 5 minutes). Stir for an additional minute after adding the garlic.
• When adding tomato paste, stir it regularly to prevent burning.
• Add the oregano, basil, sea salt, and freshly ground black pepper. Also include the crushed tomatoes. 20 minutes of uncovered simmering at a low temperature.

TO COOK THE SAUSAGE:

• Have a casing roll ready. Add some water to the pan and puncture the casing to let the fat drain for 10 to 15 minutes.
• When finished, make coins.

TO PREPARE THE CHEESE FILLING:

• Make the cheese filling while the sauce and sausage are cooking.
• Ricotta, a cup of Parmesan, beaten eggs, chopped parsley, sea salt, and freshly ground black pepper should all be combined in a big bowl. Place aside

TO ASSEMBLE THE LAYERS:

• Pour one-third of the meat sauce into a 9" x 13" x 2" casserole to start assembling the layers.
• The dish's base should be covered with a ladle of sauce.
• After that, add around half the pasta (cover the sauce with the noodles in a single layer), half the mozzarella slices, half the sausage, half the cheese mixture, and one third of the sauce.
• Add one more layer of noodles, followed by the remaining mozzarella, sausage, ricotta, and sauce.

TO BAKE:

• Bake the dish uncovered for 35 minutes, or until the sauce is bubbling, and then sprinkle the remaining 1/4 cup of Parmesan over it.