Preheat oven to 400℉/200℃. Heat 1 tablespoon oil in an iron skillet then add the onions, zucchini and garlic. Cook till zucchini is soft and slightly browned (but not mushy). Remove from pan to a bowl.
In a mixing bowl, mix together the eggs, salt, herbs, salt & pepper. Add the cooked zucchini and cheese. Heat 1 tablespoon oil in the skillet and pour in the mixture. Cook on a low flame till the bottom begins to brown, then bake for 5 minutes (till the top is set). Serve warm or at room temperature.