For the Vegetable Layers:
1 tablespoon olive oil
1 large zucchini, sliced
1 large yellow squash, sliced
1 red bell pepper, cut into strips
1 small eggplant, sliced
1 cup fresh spinach leaves
Salt and pepper, to taste
1 teaspoon Italian seasoning
For the Ricotta Mixture:
15 ounces ricotta cheese
1/4 cup grated Parmesan cheese
1 tablespoon fresh basil, chopped (or 1 teaspoon dried basil)
Salt and pepper, to taste
9–12 no-boil lasagna noodles
2 cups marinara sauce
2 cups shredded mozzarella cheese
1/2 cup grated Parmesan cheese for topping
Preheat Oven and Prepare Vegetables:
Preheat your oven to 375°F (190°C).
Heat the olive oil in a large pan over medium heat. Add the zucchini, yellow squash, bell pepper, and eggplant. Season with salt, pepper, and Italian seasoning. Sauté until the vegetables are just tender. Add the spinach at the end, allowing it to wilt. Remove from heat.
Prepare Ricotta Mixture:
In a bowl, combine the ricotta cheese, egg, 1/4 cup Parmesan cheese, basil, and season with salt and pepper. Mix well until all the ingredients are fully incorporated.
Assemble the Lasagna:
Spread a thin layer of marinara sauce on the bottom of a 9×13 inch baking dish.
Place a layer of no-boil lasagna noodles over the sauce.
Spread half of the ricotta mixture over the noodles.
Arrange half of the sautéed vegetables over the ricotta layer.
Sprinkle a layer of mozzarella cheese over the vegetables.
Repeat the layers once more: noodles, ricotta mixture, vegetables, and mozzarella cheese.
Top with a final layer of noodles, the remaining marinara sauce, and sprinkle with the remaining mozzarella and 1/2 cup Parmesan cheese.
Bake the Lasagna:
Cover the baking dish with aluminum foil. Make sure the foil does not touch the cheese to prevent sticking.
Bake in the preheated oven for 25 minutes.
After 25 minutes, remove the foil and continue to bake for another 15-20 minutes, or until the top is golden and bubbly.
Rest and Serve:
Allow the lasagna to rest for about 10 minutes after taking it out of the oven. This will help it set and make slicing easier.
Cut into squares and serve warm.
You can roast the vegetables in the oven for a different flavor profile. To roast, toss the vegetables with olive oil, salt, pepper, and Italian seasoning, and spread them on a baking sheet. Roast in a preheated oven at 425°F (220°C) until tender and slightly caramelized.
For an extra layer of flavor, consider adding sautéed mushrooms or caramelized onions to the vegetable layers.
If you want a richer tomato sauce, you can simmer your marinara sauce with herbs and a splash of red wine before assembling the lasagna.