In a large, heavy-bottomed pot or Dutch oven over medium-high heat, add the Italian sausage and ground beef. Cook, breaking the meat up with a spoon, until it is browned and no longer pink, about 8-10 minutes. Use a slotted spoon to transfer the meat to a plate, leaving about 2 tablespoons of drippings in the pot.
Add the chopped onion to the pot with the drippings. Sauté over medium heat until softened and translucent, about 5 minutes. Stir in the minced garlic and cook for another minute until fragrant. Return the browned meat to the pot. Pour in both jars of marinara sauce, then add the dried oregano and dried basil. Season with salt and pepper, and cook, stirring occasionally, until the sauce reaches the desired consistency, about 10 minutes.
Whisk together the cottage cheese, eggs, and reserved 1/4 cup of the grated Parmesan. Season with salt and pepper.
Preheat the oven to 375°F (190°C). Lay out the lasagna noodles on a lightly floured surface and cut them into 1-inch (2.5 cm) pieces.
In a 9×13 inch (22.5×33 cm) baking dish, spread a layer of the meat sauce, followed by a layer of the cut lasagna noodles. Spread the cottage cheese mixture over the noodles, then top with another layer of meat sauce and the remaining noodles and cheese mixture. Sprinkle the remaining grated Parmesan over the top.
Bake in the preheated oven for 20 minutes, then reduce the heat to 350°F (175°C) and bake for an additional 15 minutes. Let rest for 10 minutes before serving with additional sliced fresh parsley on top.
Serve hot.