Heat oven to 350 degrees. Bring a pan of water to a boil. Stir in barley; reduce to simmer. Cook until tender, 20 to 30 minutes. Drain in a colander or fine sieve, and rinse with cold water. Cover, and set aside.
Fill saucepan with water; boil. Remove cabbage's large outer leaves.You'll need 24 large leaves. Add half to boiling water; simmer until tender, about 4 minutes. Drain in a colander; cool. Repeat with remaining leaves; set aside.
In a large bowl, combine shallot, carrot, celery, pepper, tomato, raisins, turkey, cumin, coriander, cayenne, nutmeg, cloves, 1 1/2 teaspoons salt, 1/4 teaspoon pepper, and 1 cup reserved barley. Using hands, mix. Chill until ready to assemble.
Heat 1 tablespoon olive oil in a highsided saute pan on medium heat.Add onion and garlic; cook until soft, about 3 minutes. Add tomato sauce, brown sugar, parsley sprigs, and oregano sprigs. Stir to combine; bring to a boil. Reduce to gentle simmer; cover. Cook while assembling cabbage. Once cooked, the sauce can be pureed if desired.
Lay 2 cabbage leaves side by side, slightly overlapping, on a work surface. (If leaves are large, use one.) Place a heaping 1/3 cup turkey mixture on the stem end. Roll into a tight cylinder, folding in ends. Repeat with remaining leaves and mixture. Uncover sauce; place cabbage rolls in a baking pan. Spoon sauce over tops; cover. Bake 1 hour.
Meanwhile, toss reserved barley and remaining teaspoon oil, 1/4 teaspoon salt, and 1/4 teaspoon pepper. Cover; set aside.
After 1 hour, remove rolls from oven. Serve over room-temperature barley mixture, topped with sauce and chopped herbs.