This recipe produces tender, succulent ribs slathered in a chocolate-chipotle barbecue sauce that'll have you licking your fingers.
In a medium size bowl, combine all ingredients and mix well. Set aside.
Heat vegetable oil in a medium saucepan over medium-high heat. When oil begins to shimmer, add the onion and garlic and cook until onions are translucent, about 6 minutes. Add chopped tomatoes and paprika and bring to a simmer.
Cook until tomatoes have broken down, about 20 minutes, and then add the sugar and vinegar and bring to a simmer. Add chocolate and mix until incorporated. Season to taste with salt and pepper.
Using a blender or food processor, process sauce until smooth, then run through a fine mesh strainer. Set aside.
Rub ribs with the dry rub on both sides. Allow to sit overnight.
Place 1/4 of the chopped onion on a large sheet of tin foil. Drizzle 1/2 cup the barbecue sauce over the onions and place ribs bone side down on onions. Smear 1 cup more of the sauce over ribs and then encase them in foil. Repeat with remaining ribs.
Place ribs in a 250-degree oven and cook until tender, about 5 hours. Allow ribs to cool completely (in the fridge overnight is fine), then grill over high heat, basting with leftover sauce.