In medium skillet, saute onions and zucchini in oil until tender. Add cauliflower. In a bowl, stir eggs, cheese, and pepperoni until blended. Pour over vegetables in skillet. Cook over low heat about 15 minutes until set. If surface is moist, run skillet under broiler one minute or less to set the surface. Serve from skillet or slide onto serving plate. Cut into pie shaped wedges to serve.