Rub first 3 ingredients evenly over pork. Melt butter in a large nonstick skillet over medium high heat. Add pork; cook 10 minutes or until browned on all sides.
Place onion and pork in a 5 quart slow cooker. Add barbecue sauce and marinade.
Cover and cook on high 7 hours or until pork is tender and shreds easily.
Remove pork to a large bowl, reserving sauce; shred pork. Stir shredded pork into sauce. Serve as is, over a cheese-topped baked potato, in a sandwich, or over a green salad. Garnish, if desired. Makes 8 servings.
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