Heat the skillet over medium heat, then add ground beef, breaking it apart with a wooden spoon. Cook until browned and fragrant, about 5–7 minutes, then drain excess fat if needed.
Add the tomato sauce to the cooked beef, stirring to combine and letting it simmer gently for 2 minutes to meld the flavors.
Pour in the water and spread the dry lasagna noodles evenly across the surface, pressing them just below the sauce to ensure contact for even cooking.
Increase the heat to bring the mixture to a gentle simmer, then reduce to medium-low, cover the skillet, and cook for about 10–12 minutes, or until the noodles are tender and have absorbed most of the liquid. Stir occasionally to prevent sticking.
Remove the lid and sprinkle shredded mozzarella evenly over the lasagna. Cover again and cook for 2–3 minutes until the cheese is melted and bubbly.
Turn off the heat and let the lasagna sit for a minute. Then, serve hot, garnished with extra cheese or herbs if desired.
