Heat olive oil in a large skillet over medium-high heat. Add ground meat and onion. Cook, breaking up the meat with a spoon, until browned and no pink remains, about 5-7 minutes. Drain any excess fat. Add minced garlic and cook for another minute until fragrant.

Stir in the marinara sauce, water, Italian seasoning, salt, and pepper. Bring to a simmer, then reduce heat to low, cover, and let it gently simmer for at least 15 minutes while you prepare other ingredients. (If not using meat, simply combine marinara sauce, water, Italian seasoning, salt, and pepper in a saucepan and simmer.)

In a large mixing bowl, combine cottage cheese, grated Parmesan cheese, beaten egg, chopped fresh parsley (if using), salt, and black pepper. Mix until well combined.

Preheat oven to 375°F (190°C). Lightly grease a 9x13 inch baking dish.

Spread about 1 cup of the meat sauce (or plain marinara if not using meat) evenly over the bottom of the prepared baking dish.

Place 3 lasagna noodles over the sauce, slightly overlapping if necessary.

Spread half of the cottage cheese mixture evenly over the noodles.

Sprinkle 1 cup of shredded mozzarella cheese over the cottage cheese layer.

Spoon about 1.5 cups of meat sauce over the mozzarella.

Repeat the layers: 3 lasagna noodles, remaining cottage cheese mixture, remaining 1 cup shredded mozzarella cheese.

Top with the final 3 lasagna noodles.

Pour the remaining meat sauce evenly over the top layer of noodles, ensuring all noodles are covered with sauce to prevent them from drying out.

Cover the baking dish tightly with aluminum foil.

Bake for 30 minutes.

Remove the foil and bake for another 15-20 minutes, or until the cheese is bubbly and lightly golden brown.

If desired, you can broil for the last 2-3 minutes for a deeper golden crust, watching carefully to prevent burning.

Remove lasagna from the oven and let it rest for 10-15 minutes before slicing and serving. This allows the layers to set and prevents it from falling apart.