2 pounds beef flank steak
               1 Tbsp oil
               1 large onion, sliced
               4 oz chopped green chilies
               1/3 cup water
               2 Tbsp vinegar
               1 Tbsp dry mustard
               4 Tbsp chili powder
               1 Tbsp garlic powder
               1/2 tsp sugar
               1/2 tsp salt
               1/2 tsp pepper

               Place meat in slow cooker.  Mix together all remaining ingredients
               in a bowl and pour over steak.  Cook on high for 3  1/2 hrs or low 7
               hours until meat is very tender.