Slow-Grilled Pork Shoulder with Ancho Barbecue Sauce - Rick Bayless

Ingredients

• 1 (about 4 pounds) bone-in pork shoulder roast
• 1 1/4 cups New Red Chile Adobo (divided use)
• 1 1/2 tablespoons vegetable oil, olive oil, bacon drippings or butter (each will add a different character to the sauce)
• 1 small red or white onion (red will make the sauce sweeter), thinly sliced
• 1 15-ounce can diced tomatoes in juice (preferably fire-roasted)
• 1 tablespoon balsamic or sweet sherry vinegar
• 1/2 cup agave nectar or sugar
• 2 tablespoons Worcestershire
• Salt