Recipe: Barbecued Baby Back Ribs

`INGREDIENTS:`
2 tablespoons (1/4 stick) butter	2 onions, chopped	3 cups ketchup
1 12-ounce bottle chili sauce	1/2 cup apple cider vinegar	1/2 cup (packed) dark brown sugar
1/3 Dijon mustard	1/3 cup robust-flavored (dark) molasses	1/3 cup Worcestershire sauce
2 tablespoons fresh lemon juice	2 tablespoons fresh orange juice	1 teaspoon cayenne pepper
1-1/2 teaspoons liquid smoke	3 racks baby back pork ribs (about 5 pounds), each cut into 4-rib sections	1 teaspoon salt

`1`	Melt butter in heavy large saucepan over medium-high heat. Add onions and saute until softened, about 8 minutes. Add all remaining ingredients except ribs and salt and bring to boil. Reduce heat to low and simmer uncovered until thick and reduced to generous 5 cups, stirring bottom and scraping down pan sides occasionally, about 1-1/2 hours.
`2`	Place ribs in large pot. Add enough cold water to cover and 1 teaspoon salt and bring to boil. Reduce heat to low and simmer until tender, about 45 minutes. Drain. Divide ribs between 2 large rimmed baking sheets. Spread 2-1/2 cups sauce over both sides of ribs. Let stand at room temperature at least 1 hour and up to 2 hours.
`3`	Prepare barbecue (medium heat). Grill ribs until lightly charred, turning occasionally, about 10 minutes. Transfer to plates. Serve, passing remaining sauce separately.