In a 5 to 6 qt. slow cooker, mix together Heinz 57® Worcestershire Sauce, Mustard, sugar, tomato paste and onion. Season with salt and pepper if desired. Add pork, turning until well coated. Cover and cook on low heat setting for about 8 hours, or until pork is tender, turning occasionally.
To serve, remove pork from slow cooker. Pull pork into shreds using two forks. Return pork to slow cooker and stir until well mixed with sauce. Spoon about 3/4 cup onto your favorite sandwich buns and serve immediately.
TIP: If preferred, cook on high heat setting for about 4 hours, or until pork is tender, turning occasionally.