Cheesy Zucchini Quiche

Preheat oven to 350 degrees F. Very thinly slice zucchini with a mandoline or very sharp knife to equal about 4 cups (reserve any extra zucchini for another use).

Heat oil in a large skillet over medium-high heat. Add leeks, 3 cups of the zucchini slices and 1/8 teaspoon salt; cook, stirring often, until the vegetables are beginning to soften, 4 to 5 minutes. Remove from heat and let the vegetables cool slightly, about 5 minutes.

Meanwhile, whisk eggs, half-and-half, 3 tablespoons chives and the remaining 1/8 teaspoon salt in a medium bowl. Set aside.

Lightly coat a 9-inch glass pie pan with cooking spray. Spread half the vegetable mixture in the prepared pan; sprinkle with 1/4 cup feta and 1/2 cup fontina. Top with the remaining vegetable mixture and the remaining 1/2 cup fontina. Slowly pour the egg mixture evenly over the top. Arrange the remaining 1 cup zucchini slices in an overlapping circular pattern over the top and sprinkle with the remaining 1/4 cup feta. Place the pie pan on a rimmed baking sheet; bake until puffed and set in the center, 35 to 40 minutes. Sprinkle with the remaining 1 tablespoon chives. Let cool slightly before cutting.