Arrange eggplant slices in a single layer on a baking sheet coated with vegetable spray (butter). You may also wish to add onion now if desired. Lightly spray the eggplant (and onion) with cooking spray. Broil 3 inches from heat for 5 minutes; turn eggplant (and onion) over and broil an additional 5 minutes or until lightly browned. Arrange eggplant, pepper, onion, herbs, tomato, or whatever your favorite sandwich fixings are in bread. If you like cheese, place a slice on top and broil until cheese melts. Add salad dressing or spread Dijon on the top.