Seed the peppers and cut into 2 or 3 large pieces each. Place under the broiler, skin side up, until black blisters form. Remove peppers from oven and immediately place them in either a covered bowl or a paper or plastic bag for about 10 to 15 minutes. After steaming in the bowl or bag the peppers will be easy to peel.
Meanwhile, heat 2 tablespoons of the olive oil in a frying pan and add the onion slices. Cook for about 5 to 6 minutes until softened and translucent. Remove from heat and reserve.
Remove the peppers from bag or bowl and peel off the skins. Discard the skins and cut the peppers into fairly thin slices.
Place the peppers, cooked onions and any pan drippings into a bowl. Add the garlic, remaining olive oil, lemon juice and season to taste with salt and pepper. Mix well, cover and marinate for 2 to 3 hours, stirring once or twice.
Garnish the salad with chopped parsley and serve as an appetizer or to accompany cold meats.