Cut Boneless Pork Shoulder Crosswise Into 1/4 Inch Slices. Partially Freezing It Will Make Slicing Easier. In The Slow Cooker, Combine Sliced Pork, Onion, Garlic, Brown Sugar, Dry Mustard, Salt, Pepper, Ketchup, And Worcestershire Sauce; Mix Well, And Cover. Cook On Low, Stirring Occasionally, For 6 To 8 Hours Or Until The Meat Is Tender. Or : In A Dutch Oven Or Large Saucepan, Combine Pork, Onion, Garlic, Brown Sugar, Dry Mustard, Salt, Pepper, Ketchup, And Worcestershire Sauce; Mix Well. Bring To A Boil, Reduce Heat, And Cover. Simmer, Stirring Occasionally, For 2 1/2 To 3 Hours Or Until Pork Is Tender.