Heat 1 tablespoon olive oil in a large skillet over medium-high heat.
Add the diced onion, diced red bell pepper, diced zucchini, and sliced mushrooms, and cook, stirring occasionally, for 5–7 minutes until the vegetables are tender.
Stir in the minced garlic, 1/4 teaspoon dried basil, 1/4 teaspoon dried oregano, and a dash of crushed red pepper flakes; cook 30 seconds until fragrant.
Break the lasagna noodles into large pieces and add them to the skillet, spreading them evenly over the vegetables.
Pour the 24-ounce jar of pasta sauce and the 15-ounce can of undrained diced tomatoes over the noodles, pressing any noodles down so they are covered by liquid; season with salt and black pepper to taste.
Reduce the heat to medium, cover the skillet, and cook for 20 minutes, until the noodles are tender and mostly cooked through.
Remove the lid and gently stir in 1/2 cup ricotta cheese until combined.
Arrange the thin slices of fresh mozzarella over the lasagna, replace the lid, and cook 3–4 minutes until the cheese melts.
Remove the lid, sprinkle with 1/4 cup grated Parmesan and 1/3 cup chopped fresh basil, then serve warm.