1. Cook zucchini and onions in half the butter with oregano and salt till tender (about 5 minutes).
2. In blender, mix eggs, milk, cheese, bisquick, salt and remaining melted butter.
3. Mix well, about two minutes. Pour into 13-inch dish or pie plate.
4. Spread zucchini all over top. Bake 30 to 40 minutes at 375 degrees.