Preparation / Directions:
About 4 hours before serving or early in day:
Cut off roots and trim leaf ends of leeks. Cut leeks lengthwise in half to within 2 inches of root ends. Separate leaves lightly; rinse leeks with running cold water to wash away sand and grit. Cut each pepper lengthwise in half; discard seeds.
Parboil vegetables: In 8-quart saucepot over high heat, in 2 inches boiling water, heat leeks and 2 teaspoons salt to boiling. Reduce heat to low; cover and simmer 5 to 10 minutes until leeks are tender. Remove to large roasting pan. Add peppers to saucepot; over high heat, heat to boiling. Reduce heat to low; cover and simmer 5 to 10 minutes until tender-crisp; remove to same pan.
To vegetables in pan, add mushrooms, olive oil, vinegar, oregano, sugar, pepper and 1 teaspoon salt. Cover; refrigerate at least 2 hours, turning vegetables occasionally.
To broil in oven: About 40 minutes before serving, preheat broiler if manufacturer directs. Place peppers and mushrooms on rack in broiling pan, reserving marinade. About 5 to 7 inches from source of heat, broil peppers and mushrooms 10 minutes or until heated through, turning them once and brushing them with marinade.
Remove peppers and mushrooms to large platter. Place leeks on same rack in broiling pan. Broil leeks 10 minutes or until heated through, turning leeks once and brushing with remaining marinade; remove to platter with peppers and mushrooms. Pour pan juices in broiling pan over vegetables. Garnish vegetables with fresh oregano sprigs.