Step 1

Preheat the oven to 375°. Set 2 wire racks over 2 rimmed baking sheets. Arrange the zucchini slices in a single layer on the racks, brush with 1 tablespoon of the olive oil and season generously with salt and black pepper. Roast the zucchini for about 40 minutes, until just tender and lightly browned at the edges.

Step 2

Meanwhile, in a medium saucepan, heat the remaining 2 tablespoons of olive oil until shimmering. Add the onion, garlic and a generous pinch each of salt and black pepper and cook over moderate heat, stirring occasionally, until softened, about 7 minutes. Stir in the tomato paste for 1 minute, then add the chopped tomatoes and crushed red pepper and bring to a simmer. Cook, stirring occasionally, until the sauce is slightly thickened, about 20 minutes. Season with salt and black pepper.

Step 3

In a medium bowl, combine the ricotta and the 1 cup of Parmesan with the egg, basil and thyme. Season with salt and pepper.

Step 4

Increase the oven temperature to 400°.  Lightly oil a 2-quart oval baking dish. Spread 3/4 cup of the tomato sauce in the dish and arrange a single layer of zucchini slices on top. Spread 1 cup of the ricotta mixture over the zucchini, then sprinkle with about one-third each of the provolone and mozzarella. Spoon 1 cup of the tomato sauce over the cheeses. Arrange another layer of zucchini over the tomato sauce, spread the remaining ricotta mixture on top and sprinkle with another one-third of the provolone and mozzarella. Spoon the remaining tomato sauce on top. Arrange the remaining zucchini slices over the sauce, then top with the remaining provolone and mozzarella.

Step 5

Place the baking dish on a baking sheet and bake the zucchini lasagna for 30 to 35 minutes, until the sauce is bubbling and the cheese is beginning to brown. Let stand for about 20 minutes before serving.