Slow-Cooked BBQ Beef Short Ribs

3 pounds beef short ribs
1 onion, thinly sliced
1 cup water
2 teaspoons Beef Flavored Bouillon Granules
1 cup hickory smoked barbecue sauce
3 tablespoons dark brown sugar
1 tablespoon Dijon mustard
2 tablespoons cornstarch dissolved in a small amount of water
1 Heat a large skillet over medium high heat and brown the short ribs on all side. Place the ribs in a slow cooker and top with the onions. In a medium bowl, combine the water, beef granules, barbecue sauce, brown sugar and Dijon mustard. Pour sauce over ribs, cover and cook on low for about 6-7 hours, or until tender. Add the cornstarch mixture and continue to cook until the sauce thickens, about 20 minutes.