Braised Short Ribs with Dijon Mustard

Boil wine in a 2-quart heavy saucepan until reduced to about 1 cup. While wine is reducing, pat ribs dry and cut crosswise into 1-rib pieces (each about 2 1/2 inches long). Season well with salt and pepper. Heat a dry 5-quart heavy pot over moderately high heat until hot, then brown ribs well in 3 batches on all sides, about 8 minutes for each batch. Transfer browned ribs with tongs to a bowl. Reduce heat to moderate and brown shallots well in fat remaining in pot, stirring. Transfer with a slotted spoon to another bowl. Stir wine and mustard into juices in pot. Add ribs and simmer, covered, 1 3/4 hours. Gently stir in shallots and tomatoes and continue to simmer, covered, without stirring, until meat is very tender, about 40 minutes. Carefully transfer ribs, shallots, and tomatoes to a platter and skim off any fat from cooking liquid. Season sauce with salt, pepper, and mustard to taste and pour over ribs.