Heat olive oil in a large deep skillet over medium heat.
Add chopped onion and cook for 3-4 minutes until softened.
Add minced garlic and cook for 1 minute until fragrant.
Add ground beef to the skillet and cook, breaking it apart with a spoon, until browned and cooked through, about 6-8 minutes.
Drain excess fat from the skillet if necessary.
Stir in dried oregano, dried basil, salt, and black pepper.
Pour in the marinara sauce and water, stirring to combine.
Bring the sauce to a simmer.
Add broken lasagna noodles to the skillet, pressing them down gently to submerge in the sauce.
Cover the skillet with a lid and cook on low heat for 15 minutes, stirring occasionally to prevent sticking, until noodles are tender.
In a small bowl, combine ricotta cheese, egg, and grated Parmesan cheese until smooth.
Remove the skillet from heat and dollop the ricotta mixture evenly over the noodles and sauce.
Sprinkle shredded mozzarella cheese evenly on top.
Cover the skillet again and let it sit for 5 minutes off the heat to allow the cheese to melt.
Garnish with chopped fresh parsley before serving.