1Lay eggplant on its side, cutting a thin slice from the eggplant to form a flat base, if necessary. Horizontally slice off the top about one-fourth of eggplant. Carefully scoop out pulp, leaving a 1/4 inch shell; chop enough pulp to measure 3 cups. Reserve remaining pulp for another use. Set eggplant shell aside.
2Heat oil in a heavy saucepan over medium-low heat; add 3 cups chopped eggplant, green peppers, onions, & garlic. Cover & cook 15 minutes, stirring occasionally. Add mushrooms & next 7 ingredients. Bring to a boil; cover, reduce heat, & simmer 15 minutes or until eggplant is tender, stirring occasionally. Cool slightly; cover & chill at least 2 hours.
3Line eggplant shell with lettuce. Spoon dip into lettuce-lined shell; serve with pita chips or bagel chips.