1-Preheat oven to 190°C (375°F). Cook the 12 lasagna noodles in salted water until al dente, then drain and rinse with cold water to keep them from sticking.

2-In a deep pan or Dutch oven over medium-high heat, brown the 450 grams ground beef, then add the 1/2 cup diced onion and cook until softened.

3-Add the 3 minced garlic cloves, 1 teaspoon salt, 1/2 teaspoon black pepper, and 1/2 teaspoon oregano; cook for another minute. Stir in the 900 milliliters marinara sauce and bring to a simmer, then remove from heat.

4-Spread 120 milliliters (1/2 cup) of the meat sauce on the bottom of a casserole dish. In a large bowl, mix together the 425 grams ricotta cheese, 1 large egg, 1/4 cup shredded Parmesan cheese, 1 1/2 cups (about 170 grams) shredded mozzarella cheese, and 1/4 cup chopped parsley.

5-Lay cooked noodles flat, spread about 60 milliliters (1/4 cup) cheese mixture on each, add a heaping tablespoon of meat sauce in the center, then roll the noodles up and place them seam-side down in the casserole dish.

6-Spread remaining meat sauce on top and sprinkle with remaining mozzarella cheese. Cover with foil tented to avoid cheese contact and bake covered for 40 minutes. Remove foil and broil for 2 to 3 minutes until cheese is lightly golden, then garnish with parsley and serve.