Preheat oven to 325°.
Sprinkle short ribs lightly with salt and pepper. Using a sauté pan, sear short ribs in a small amount of oil and remove from sauté pan. Add celery, onion, carrots, bay leaves, and garlic and sauté for 1 minute. Add wine, broth, vinegar, rosemary, and thyme to the pan. Stir gently to mix, and scrape the browned bits free.
Place liquid and short ribs in a casserole pan, cover with foil, and bake until meat is very tender when pierced, 2-1/2 to 3-1/2 hours, depending on the size of the short ribs. Remove short ribs from braising liquid and keep warm. Skim and discard any fat from braising liquid and strain sauce into a saucepan. Boil, uncovered, over medium heat stirring often until it reduces to approximately 2 cups, salt and pepper to taste.
Mix 1-1/2 tablespoons cornstarch with 2 tablespoons of water in a small bowl until smooth. Stir into braising liquid until mixture boils and thickens. Ladle sauce over short ribs, salt and pepper to taste, and garnish with a rosemary or thyme sprig. Makes 4 servings.