- In a saucepan over medium heat, brown the onion and garlic in the oil. Add the tomatoes. Simmer for about 30 minutes. Add the basil. Season with salt and pepper. Set aside.
- With two racks in the middle positions, preheat the oven to 425°F (220°C). Line two baking sheets with parchment paper or silicone mats.
- On one baking sheet, combine the eggplant with 3 tbsp (45 ml) of the oil. Season with salt and pepper. On the second sheet, combine the bell peppers and zucchini with the remaining oil (1 tbsp/15 ml). Season with salt and pepper. Space out the vegetables and make sure they’re lying flat. Bake both trays for 15 to 20 minutes or until the vegetables are roasted. Set aside.
- In a saucepan over medium heat, melt the butter. Add the flour and cook for 1 minute while stirring with a whisk. Add the milk while whisking. Bring to a boil. Let simmer gently for 5 minutes while stirring constantly so the sauce doesn’t stick to the bottom of the saucepan. Add the Parmesan and nutmeg. Season with salt and pepper. Set aside.
- With the rack in the middle position, adjust the oven temperature to 375°F (190°C).
- In a large non-stick skillet over medium-high heat, melt the butter. Add the spinach and cook for 1 minute or until just wilted.
- In a 13 x 9-inch (33 x 23 cm) baking dish, spread 1 cup (250 ml) of the tomato sauce and cover with a layer of noodles. Top with the eggplant and spinach. Add 1 cup (250 ml) of tomato sauce and half of the béchamel. Sprinkle with 3/4 cup of the mozzarella and cover with a layer of noodles. Spread 1 cup (250 ml) of the tomato sauce, top with the zucchini and bell peppers and the remaining béchamel. Cover with a final layer of noodles, the remaining tomato sauce and the remaining cheese. Cover the entire surface with the raw zucchini ribbons, in a woven pattern if desired. Sprinkle with the Parmesan.
- Bake for 45 minutes, and then brown under the broiler for a couple of minutes. Let rest for 15 minutes before serving.
Make sure to buy oven-ready lasagna noodles (as in, pre-cooked and ready to use). Fast and simple!