In a large pot of salted boiling water, cook the lasagna noodles according to package instructions until al dente. Drain and set aside.
In a large skillet, heat the olive oil over medium heat. Add the chopped onion and minced garlic, cooking until the onion is soft and translucent, about 3-4 minutes.
Add the ground beef or turkey to the skillet. Cook until browned, breaking it up into small pieces with a spatula. Drain any excess fat.
Stir in the grated carrot, shredded zucchini, and diced bell pepper, cooking for an additional 3-4 minutes. Add the crushed tomatoes, dried oregano, dried basil, salt, and pepper. Simmer for about 10 minutes, allowing flavors to meld.
In a large baking dish (9x13 inches), spread a thin layer of the meat sauce on the bottom. Layer 4 cooked noodles over the sauce, followed by half of the ricotta cheese, half of the meat sauce, one cup of mozzarella cheese, and a sprinkle of Parmesan cheese.
Place another layer of 4 noodles, the remaining ricotta cheese, the remaining meat sauce, and the remaining mozzarella and Parmesan cheeses. Top with the final 4 noodles and the rest of the mozzarella cheese.
Cover the baking dish with aluminum foil and bake in the preheated oven for 25 minutes. Remove the foil and bake for an additional 15-20 minutes, or until the cheese is bubbly and lightly browned.
Allow the lasagna to cool for about 10-15 minutes before slicing. Garnish with fresh basil leaves before serving.
Notes
Allow the lasagna to cool before slicing for cleaner pieces.