250ml chicken stock

½ cup brown sugar

¼ cup tomato paste

2 tbsp soy sauce

2 tbsp Dijon mustard

4 garlic cloves, minced

1 large onion (sliced)

salt to taste

125 mls red wine vinegar

Place sauce ingredients into slow cooker bowl. Add beef and turn it until completely coated. Cover and cook on low for 8-10 hours or on high for 4-5 hours. Turn occasionally if possible. Remove beef, place on plate and cover to keep warm. Skim any fat from slow cooker juices, strain remaining liquid through sieve. Place strained liquid into large frying pan. Set solids aside in small bowl. Bring liquid to boil and gently boil for 15 minutes, stirring occasionally until sauce has thickened a little and reduced by half. If you wish, add flour to sauce to thicken it. Shred beef using fork and add to sauce mixture. Add reserved solids and stir through. Serve hot on rolls or with mashed potato.