This recipe is from the Mitchell Delicatessen, Nashville, Tennessee. This sandwich is only served on Mondays and is extremely popular. The giardiniera recipe makes much more than is needed for the sandwich....Enjoy!
Whisk all flank steak marinade ingredients together in a large bowl. Cover flank steak and marinate for 24 hours in a refrigerator.
To make Giardiniera: Julienne green bell pepper, red bell pepper, celery, carrots, red onion, yellow onion, green beans and cucumber. Add salt and toss. Cover with cold water and refrigerate for 24 hours. Strain the vegetables and rinse well with cold water. Drain and place in large bowl. Add remaining ingredients and let it set for 24 hours.
Grill flank steak to personal preference. Allow to rest 10 minutes. Slice thinly. Place flank steak on a split ciabatta roll and top with decent amount of giardiniera.