Peel and chop the onion, garlic, and carrots into small pieces.
In a hot, oiled skillet, sauté the onion and garlic, then add the carrots and let them soften for a few minutes.
Add the tomato paste and ground meat. Sear over high heat, then reduce the heat.
Once the meat is cooked, add the tomato sauce, a bit of water, spinach, salt, pepper, paprika, oregano, and basil. Mix well and let it simmer until the spinach wilts.
Break the lasagna sheets and add them to the mixture, cover, and simmer for 5 minutes.
Stir again, add slices of mozzarella, cover, and simmer for an additional 5 minutes before serving. Alternatively, you can place the skillet in the oven for 5 minutes to lightly gratinate the mozzarella.