Preheat the oven to 400°F (200°C).

In a large bowl, toss the sliced eggplant, zucchini, red and yellow peppers, onion, and minced garlic with 2 tablespoons olive oil. Season with salt and pepper.

Spread the vegetables evenly on a baking sheet in a single layer. Roast for 20–25 minutes, or until tender and starting to brown.

While the veg roast, cook the lasagna noodles according to package directions. Drain and lay them flat so they don’t stick.

In a medium bowl, mix ricotta, Parmesan, egg, and salt and pepper to taste. Stir until smooth.

Spread a thin layer of tomato sauce across the bottom of a 9x13-inch baking dish.

Lay down 4 noodles over the sauce, trimming if necessary to fit.

Spread half of the ricotta mixture over the noodles in an even layer.

Top the ricotta with a layer of the roasted vegetables.

Repeat: another layer of sauce, 4 noodles, the remaining ricotta, and the remaining roasted vegetables.

Top with the remaining tomato sauce and sprinkle extra Parmesan over the top.

Cover the baking dish tightly with foil and bake for 30 minutes.

Remove the foil and bake uncovered for an additional 10–15 minutes, until the cheese is melted and bubbly and the edges are hot.

Let the lasagna cool for about 5 minutes before slicing and serving.