Zucchini and Bell Pepper Frittata

This recipe came from an estate sale. I obtained it when I purchased the family collection from the Henson Estate in Dallas, Texas in 1982.
 * Contributed by Catsrecipes Y-Group

Ingredients

 * ⅓ cup finely chopped white onion
 * 1 cup thinly sliced zucchini
 * ½ cup finely chopped red bell pepper
 * ½ cup finely chopped green bell pepper
 * 1½ tablespoons olive oil
 * 4 large eggs
 * ⅔ cup freshly grated Parmesan
 * 2 tablespoons minced fresh parsley leaves

Directions

 * 1) In 9-inch non-stick skillet cook onion, zucchini and peppers with salt and black pepper to taste in 1 tablespoon of the oil over moderate heat stirring, for 10 minutes.
 * 2) In a bowl whisk together the eggs, ⅓ cup of the Parmesan and the parsley then add the vegetable mixture and stir until it is combined well.
 * 3) In the skillet heat the remaining ½ tablespoon oil over moderate heat until it is hot but not smoking and pour in egg mixture distributing the vegetables evenly and cook without stirring for 10 minutes.
 * 4) Sprinkle the remaining ⅓ cup Parmesan over the top and broil frittata under preheated broiler about 4 inches from heat for 4 minutes.
 * 5) Let cool in skillet 5 minutes then run knife around edge.
 * 6) Slide frittata on serving plate and cut into wedges.
 * 7) Serve warm or at room temperature.