Heat oven to 425°F. Cut lemons in half crosswise. Rub lemons and garlic with 1 tablespoon of the oil. Place lemon halves, cut sides down, and garlic in 9-inch glass pie plate. Roast uncovered 25 minutes or until lemon peel is golden brown and very soft. Cool slightly.
Reserve 1/3 cup beans. In food processor, place remaining beans, 1/4 cup reserved bean liquid, remaining 2 tablespoons oil, the salt and red pepper. Add roasted garlic. Squeeze juice and pulp from roasted lemons into blender. Cover; process until smooth.
Spoon dip into serving bowl; stir in reserved 1/3 cup beans and 2 tablespoons parsley. Sprinkle with additional parsley. Serve with vegetables or pita wedges.