Grate zucchini. Using a food processor makes this a quick job. To prevent the quiche from being watery, zucchini must be well drained. Put the grated zucchini in a colander over a bowl. Sprinkle with salt and toss. Place another smaller bowl on top of the grated zucchini in the colander and weigh it down with something heavy, like a large can. Let sit until it starts to release water, then press down occasionally for 20 minutes or so. Squeeze out remaining water with a towel or your hands until you have 2 cups of drained zucchini.
Preheat oven to 350°F. Lightly oil or spray a 10-inch quiche dish.
While zucchini is draining, sift the flours and baking powder in a small bowl.
In a large bowl, combine the beaten eggs, milk, cheddar cheese, feta cheese, onion, basil, oregano and well-drained zucchini.
Add the dry ingredients to the wet ingredients and stir well to combine.
Transfer the mixture to the baking dish. Arrange halved cherry tomatoes on top, pressing gently into the mixture.
Bake at 350°F. for 45- 50 minutes or until center is set and knife inserted comes out clean.
Garnish with extra herbs, if desired. Let stand for 5 minutes before slicing into wedges.
Adding an extra teaspoon of coconut flour may help absorb excess moisture created by the zucchini or tomatoes.Cover and refrigerate leftovers. Cover with foil and reheat in the oven.