Preheat oven to 400 degrees F and spray 9" pie dish with cooking spray well. Set aside.
In a large bowl, add shredded zucchini, sprinkle with salt and mix. Let sit for 5-10 minutes then give it a good squeeze to extract as much water as possible, working in batches. I do it by placing zucchini into a linen towel and wringing into a ball. Transfer to a large bowl.
To a bowl with squeezed zucchini, add eggs, cottage cheese, cheese, herbs, flour, onion flakes, garlic powder, salt and pepper. Stir with a spatula until well combined.
Transfer mixture to previously prepared baking dish and bake for 45-50 minutes or until it's no more jiggly in the middle and toothpick inserted in the center comes out clean.
Remove quiche from the oven and let cool on a wire rack for about 2 hours. Loosen the edges with spatula and cut into 8 slices. Enjoy warm or cold (I love cold quiche!).
Notes
Make ahead quiche mixture and refrigerate for up to 1 day. After bake as per recipe. If you need to make quiche ahead 2 days in advance, you can prep zucchini and grate cheeses, then refrigerate separately. Helps a lot!
Store: Refrigerate leftovers covered for up to 5 days.
Freeze: In an airtight container for up to 3 months. Unsliced will stay more moist. Slices are easier to thaw but use faster.
Reheat quiche? I love mine cold. It is so good! If you must, I recommend a microwave otherwise it will dry out in the oven.
Air fryer: Line air fryer basket with unbleached parchment paper and spray well with cooking spray. Add mixture, level with spatula and bake in preheated air fryer to 320 F degrees for 30 minutes. Do toothpick test in the center for doneness.