Preheat your oven to 375°F (190°C).

Cook the lasagna noodles according to the package instructions. This typically takes about 8-10 minutes. Drain them and set aside to cool.

Sauté the vegetables by heating olive oil in a pan over medium heat. Add sliced zucchini, yellow squash, and chopped red bell pepper. Cook for 5-7 minutes until they are tender and fragrant.

Add the chopped spinach to the pan and stir until just wilted. Season with salt, pepper, and Italian seasoning.

Spread a layer of marinara sauce on the bottom of a baking dish.

Layer the noodles on top of the sauce, followed by half of the sautéed vegetable mixture, half of the creamy ricotta, and a generous layer of mozzarella cheese.

Repeat the layering process, finishing with lasagna noodles, marinara sauce, mozzarella, and grated Parmesan on top.

Cover the baking dish with foil and bake for 25 minutes, then remove the foil and bake for another 15 minutes until the cheese is bubbly and golden brown.

Cool for 10 minutes before serving.