Set oven control to broil. Place poblano peppers on rack in broiler pan. Broil peppers 4 to 5 inches from heat until skins blister, about 5 minutes on each side. Wrap in towels; let stand 5 minutes. Peel peppers carefully, starting at stem end. Cut a slit lengthwise down side of each pepper. Carefully remove seeds and membranes; rinse. Fill each pepper with 1/4 cup cheese; coat with bread crumbs. Cover and refrigerate 20 minutes. Beat egg whites, salt and cream of tartar until stiff. Beat egg yolks until thick and lemon colored, about 5 minutes; fold into egg whites. Heat vegetable oil (1 to 1 1/2 inches) to 375°. Dip each pepper into egg mixture. Fry 1 pepper at a time, turning once, until puffy and golden brown, about 3 minutes. Place peppers on paper towels on cookie sheet; keep warm in 200° oven. Heat tomato juice, casera sauce and ham to boiling. Pour over peppers. Garnish with sour cream and cilantro. 8 Servings.