Zucchini Lasagna

1. Preheat the oven to 375°F.
2. In a large straight-sided skillet set over medium heat, heat 2 tablespoons of the oil. Add the onion and red pepper flakes and cook, stirring occasionally, until the onion is tender, about 8 minutes. Add the turkey and cook, breaking up any large pieces with the back of a spoon, until brown throughout, 3 to 4 minutes. Add the tomatoes and bring the mixture to a boil. Reduce the heat to medium and simmer until it thickens, about 20 minutes. Stir in the oregano and salt. Let cool.
3. Slice the zucchini lengthwise into thin strips (about 1/8 inch thick). Put 5 or 6 zucchini slices, overlapping slightly, in the bottom of an 8 x 8-inch baking dish. Top with 1 cup of the sauce. Dot with 1/4 cup of the ricotta. Repeat the layers twice, alternating the direction of the zucchini. Top with the remaining zucchini and brush the top with the remaining 1/4 teaspoon oil. Dot with the remaining 1/4 cup ricotta and season with the black pepper. Top with the Parmesan cheese.
4. Bake for 50 to 60 minutes, until the lasagna is bubbling and the top is brown. Let stand for 10 minutes before serving.