In a deep pan over medium heat, brown the ground beef and Italian sausage with a chopped yellow onion until fully cooked and no longer pink, about 8-10 minutes. Drain excess fat, then add minced garlic, marinara sauce, oregano, and season with salt and black pepper. Simmer for 15 minutes until the sauce thickens, then set aside to cool.

Bring a large pot of salted water to a rolling boil, then add the lasagna noodles and cook for 2 minutes less than the package instructions suggest—aim for al dente. After about 8 minutes, carefully drain the noodles in a colander and lay them flat on parchment paper to prevent sticking. Let them cool while you prepare the filling.

In a mixing bowl, combine cottage cheese, beaten egg, grated Parmesan cheese, dried parsley, and a dash of salt and pepper. Stir until all the ingredients are well blended and creamy.

Preheat your oven to 350°F (175°C) and grease a baking dish. Start by spreading a thin layer of the meat sauce on the bottom. Place 4 noodles across the sauce, followed by half of the cottage cheese filling. Repeat the layering process with more meat sauce and another set of noodles, ending with a final layer of meat sauce topped with mozzarella cheese.

Once assembled, place the lasagna in the preheated oven and bake for 35-40 minutes. After baking, let the lasagna rest for 10 minutes to help the layers set before slicing.