Build a charcoal fire or preheat a gas grill. Set up the grill for indirect heat (300 degrees F). If using wood chips, place the soaked chips directly on the charcoal or in the smoking box of the gas grill.
Remove the silver skin from the back of the ribs, if desired, and rub liberally with the Hot and Sticky BBQ Rub. Let sit covered for 15 to 20 minutes.
Place the ribs bone-side down onto the center of the grill grate or in a rib holder or rack, making sure they are not over a direct flame. Grill covered until the meat is tender and has pulled back from the ends of the rib bones, 2 to 3 hours. Leave the ribs untended for the first 30 minutes-this means no peeking (especially important if using wood chips). If the ribs start to burn on the edges, stack them on top of one another in the very center of the grill and lower your fire slightly.
Brush the ribs with the Spicy Cola Barbecue Sauce 20 minutes before the end of cooking, unstacking the ribs if necessary. Let rest for 10 minutes, and then cut into individual portions. Warm the remaining sauce in a saucepan and serve on the side.
Combine the brown sugar, white sugar, molasses powder, salt, paprika, black pepper, chili powder and cayenne in a medium bowl and mix well. Store in an airtight container for up to 6 months.
Melt the butter in a heavy saucepan and saute the garlic and onions until translucent, about 10 minutes. Add the ketchup, sugar, vinegar, Worcestershire, tomato paste, chili powder, salt, black pepper and cola and simmer until the flavors have blended, about 15 minutes. Stir and continue cooking until the sauce begins to thicken, 20 to 30 minutes longer, and then taste and adjust the seasonings with salt and black pepper, if desired. Remember, the ribs will have plenty of spice rub on them, so don't over-season the sauce.
Let the sauce cool until it is warm but no longer "boiling" hot, about 10 minutes. Puree with an immersion or traditional blender (this will make the sauce thicker). Continue to let cool. Brush on food 5 to 15 minutes before the end of cooking time, or keep tightly covered in the refrigerator for up to 2 weeks.
This rub is good for seasoning pork tenderloin, ribs, beef, chicken, smashed grilled potatoes and pineapple.