Heat the olive oil in a large 12-inch skillet or Dutch oven over medium-high heat.
Add the diced onion and sauté for about 5 minutes, stirring occasionally, until the onion begins to soften.
Add the minced garlic and cook 1 minute more, stirring so it doesn't brown.
Add the ground beef and cook until browned, breaking it up with a spoon as it cooks.
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 gently to combine.
Cover the skillet and reduce heat to medium-low; simmer for 20–25 minutes, stirring occasionally, until the noodles are tender and cooked through.
Taste and add salt as needed, adjusting other seasonings if desired; stir well.
Drop spoonfuls of the ricotta evenly over the top and gently stir a few times to incorporate without overmixing.
Reduce heat to low, arrange the mozzarella slices over the surface, cover, and cook 2–3 minutes more until the mozzarella melts.
Sprinkle the torn basil over the lasagna, distribute evenly, and serve immediately.