Preheat your oven to 375°F (190°C). Bring a large pot of salted water to a boil, then add the lasagna noodles, cooking until al dente, about 8-10 minutes. Drain and lay flat on parchment paper to cool.

In a large skillet over medium-high heat, add the ground beef and sauté until browned, around 5-7 minutes. Mix in diced onion and cook until softened, approximately 3-4 minutes. Stir in minced garlic, dried oregano, sea salt, black pepper, and marinara sauce; let simmer for about 5 minutes.

In a mixing bowl, combine ricotta cheese, large egg, shredded Parmesan, 1.5 cups of shredded mozzarella, and chopped parsley. Stir well until evenly blended and creamy.

Lay out cooked noodles on a clean surface. Spread cheesy filling over each noodle, leaving edges free. Add meat sauce in center and roll up from one end to the other.

Spread remaining meat sauce at the bottom of a casserole dish. Place roll-ups seam-side down and pour leftover meat sauce on top. Sprinkle remaining mozzarella and cover with foil.

Bake covered for about 40 minutes. Remove foil and broil for an additional 2-3 minutes, until cheese is bubbly and golden brown.

Let roll-ups cool for 5 minutes before serving. Garnish with parsley and serve hot.