1-First Step: Prep and par-bake the crust* Preheat oven to 350°F.* On a lightly floured surface, roll the 9-inch refrigerated pie dough to about a 12-inch diameter. Fit it into a 9-inch deep pie dish, trim excess, and crimp the edges. Prick the crust bottom a few times with a fork to prevent bubbles.* Place the fitted crust on a baking sheet and par-bake for 10 to 15 minutes until it is lightly baked and just beginning to color. This step helps prevent a soggy bottom when the moist zucchini filling is added.

2-Second Step: Sauté the aromatics and zucchini* Use a medium skillet for this step.* Heat 1 tablespoon olive oil in a skillet over medium heat.* Add 1/4 cup diced red onion and 1 large minced garlic clove; sauté for about 30 seconds until aromatic.* Add the thinly sliced zucchini, 1/2 teaspoon of the 1 teaspoon salt, and pepper to taste. Cook 7 to 8 minutes, stirring occasionally, until the zucchini softens and excess moisture mostly evaporates.* Use a slotted spoon to transfer three-quarters of the cooked zucchini to the par-baked crust, leaving some in the pan for seasoning adjustments.

3-Third Step: Make the custard* In a medium bowl, whisk the custard ingredients until smooth.* Crack 6 large eggs into a bowl and add 1/2 cup skim milk.* Fold in 1/2 cup part-skim ricotta, 1/2 cup part-skim shredded mozzarella, 2 tablespoons of the grated Parmesan, and 2 tablespoons chopped basil.* Add the remaining 1/2 teaspoon salt and pepper to taste, then mix until evenly combined.

4-Fourth Step: Assemble the quiche* Pour the egg and cheese mixture over the zucchini in the par-baked crust, spreading gently so it settles around the vegetables.* Top with the remaining cooked zucchini and sprinkle the remaining 2 tablespoons grated Parmesan across the top.* To prevent the crust edges from browning too quickly, cover them with foil or a pie crust shield.

5-Final Step: Bake and rest* Bake at 350°F for 50 minutes to 1 hour, until the eggs are set and the top is nicely browned. A knife inserted near the center should come out clean.* Remove from oven and cool for at least 10 minutes before slicing to allow the custard to settle for clean slices.* Garnish with additional chopped basil and serve warm or at room temperature.