1/2 cup vegetable oil
1/4 cup red-wine vinegar
1/2 cup firmly packed dark-brown sugar
1/2 cup soy sauce
2 cups ketchup
1 teaspoon garlic powder or garlic salt
1 large onion, peeled and coarsely chopped
2 tablespoons Worcestershire sauce
5 pounds boneless pork shoulder roast, fat trimmed
Barbecue sauce, for serving

Whisk the oil, vinegar, brown sugar, soy sauce, ketchup, garlic powder, onion and Worcestershire sauce together in a mixing bowl. Pour into a large, zip-close plastic bag. Place the pork in bag with marinade, seal bag and turn pork to coat. Refrigerate overnight, turning bag once or twice.

Pour entire contents of bag into insert of a 5- to 7-quart slow cooker. Cover and cook on low for 10 hours, until pork is fork-tender. Remove from slow cooker, cover with foil and let rest for 15 minutes. Meanwhile, skim off any fat from sauce.

Using 2 forks, shred meat, then return it to sauce. At this point, pork may be refrigerated for up to 5 days or frozen for up to 2 months. Serve warm, with additional barbecue sauce. For sliders, pile meat into soft rolls and serve with slaw and baked beans.

Makes 10 to 12 servings.

— Recipe from Diane Phillips, author of "Slow Cooker: The Best Cookbook Ever" (Chronicle Books 2009, 544 pp., $24.95).