Preheat oven to 375 degrees. In a large skillet, saute the zucchini and onions in the margarine until softened and onion are translucent. Stir in the parsley, salt, pepper, garlic powder, basil and oregano.
In a large bowl, combine the eggs, cheese and mustard. Add the zucchini mixture, stir and mix well.
Pour zucchini mixture into the pie shell. Bake in 375 degree oven for about 20-25 minutes or until golden. Cool slightly before slicing.