Combine molasses, pickling salt and water in a 6 quart container. Add pork shoulder, submerging it completely in the brine. Cover and let sit in refrigerator or cooler on ice overnight (8 to 12 hours).
In a small skillet over medium low heat, toast coriander, cumin, fennel and peppercorns until fragrant, 1-2 minutes. Using a spice grinder or mortar and pestle, grind into a fine powder. Transfer to a bowl and mix with the remaining ingredients.
Prepare the bbq sauce by combining ingredients in a medium pot. Simmer over medium low heat for 15-20 minutes, stirring occasionally until deepened in color. Season with hot sauce to taste.
Preheat smoker to 210 degrees F. Place pork shoulder in the smoker and cook for 10 hours (or as many as 12), maintaining temperature. Meat should easily pull from the bone. Temperature should be between 185 and 195 F.
Remove from smoker and let sit for one hour.
Pull meat apart with 2 forks. Serve with bbq sauce, on buns (if desired), red cabbage slaw and beans.
Recipe by Weekend Table at https://weekendtable.com/2013/07/07/pulled-pork/