Preheat the oven to 350°F (175°C) and lightly grease a 9x13-inch baking dish.
If needed, cook the lasagna noodles according to package directions; drain and set aside.
In a large mixing bowl, combine grated carrots, grated zucchini, thawed and drained spinach, chopped bell pepper, diced tomatoes, drained tomato sauce, sliced or chopped mushrooms, oregano, dried basil, onion powder, garlic powder, and salt to taste; stir until evenly mixed.
Spread a layer of noodles in the bottom of the prepared baking dish.
Sprinkle 1/2 cup of the grated Parmesan over the noodles, then spread half of the veggie mixture evenly on top.
Add another layer of noodles, sprinkle another 1/2 cup Parmesan, and spread the remaining veggie mixture over them.
Top with a final layer of noodles, the remaining Parmesan (about 1/2 cup), and then sprinkle the grated mozzarella evenly over the top.
Bake in the preheated oven for 40 minutes, until cheese is melted and the lasagna is heated through.
Remove from the oven and let rest briefly, then garnish with chopped fresh basil if desired before serving.