Heat the 12-inch skillet or Dutch oven over medium-high and add the olive oil and diced onion; sauté for about 5 minutes, stirring occasionally, until the onion begins to soften.
Add the minced garlic and cook 1 minute, stirring so it does not burn.
Add the ground beef and cook, breaking it up with a spoon, until browned and no longer pink.
Stir in the Italian seasoning and black pepper until evenly distributed.
Add the broken lasagna noodles to the skillet, then pour in the diced tomatoes with their juice, the tomato sauce, and the water; stir to combine and submerge the noodles.
Cover the pan and reduce heat to medium-low; simmer for 20–25 minutes, stirring occasionally, until the noodles are tender and cooked through.
Taste and season with salt (and more pepper or Italian seasoning if desired), then stir everything to distribute the seasoning.
Dollop the ricotta by tablespoonfuls evenly over the top and gently stir a few times to incorporate without overmixing.
Reduce heat to low, arrange the mozzarella slices evenly over the skillet, cover, and heat 2–3 minutes until the mozzarella melts.
Sprinkle the torn basil over the lasagna, distribute evenly, and serve immediately.