For the ribs: Preheat the oven to 325 degrees F.
In a small mixing bowl, add the light brown sugar, espresso powder, mustard powder, paprika and cayenne.
Sprinkle the ribs with salt and pepper, then generously rub with the spice blend. Place on a foil-lined baking sheet, add the apple juice and cover with foil. Place in the oven and cook until tender, about 1 hour 45 minutes.
For the BBQ Sauce: Meanwhile, combine the tomato sauce, chicken stock, Southern Comfort, brown sugar, vinegar, Worcestershire, hot sauce, garlic, onion, a drizzle of oil and some ground pepper in a small saucepan. Bring to a simmer and cook at a low bubble for 15 to 20 minutes. Remove and discard the onion and garlic.
Carefully remove the baking sheet from the oven and pour off the liquid. Place under the broiler and cook until lightly golden brown in color, about 3 minutes. Brush the ribs with 1 to 2 cups of the BBQ Sauce, and broil again, about 3 minutes more.