Remove the membrane from the back of the ribs by sliding a dinner knife under the membrane and over the bone. Lift and loosen the membrane until it tears. Grab the edge of the membrane with a paper towel and pull it off. It might come off in one big piece of you will have to remove it in smaller pieces. This is ESSENTIAL.
In a small bowl combine all ingredients for the homemade rub and stir until combined.
Spread 4 Tablespoons of yellow mustard evenly over the ribs covering completely. Next, spread the dry rub over the ribs covering completely. Wrap in plastic wrap so they are completely covered. Place in fridge to rest a minimum of 2 hours, or overnight for best results.
Prepare your smoker according to manufacture's directions to a heat of 225 degrees Fahrenheit.
Place ribs, bone side down, on the preheated smoker and smoke for 3 hours at 225 degrees Fahrenheit.
Mix together 1/2 cup apple juice and 1/2 cup water in a spray bottle and spritz ribs with mixture every half hour.
After 3 hours remove ribs from smoker but leave smoker on at same temperature.
Lay two pieces of tinfoil out on counter (enough to wrap ribs in). Evenly smear the 2 Tablespoons yellow mustard down the middle of foil about 4 inches wide. Place butter slices evenly between the foil pieces down the middle of foil. Next lay the ribs on the foil, bone side done. Tightly seal the foil. Place ribs back in the smoker at 225 degrees Fahrenheit for 2 hours.
In a small mixing bowl, combine dijon mustard, honey, BBQ sauce, brown sugar and garlic to make the finishing sauce.
After 2 hours, remove the ribs from the smoker and remove foil. Coat ribs with finishing sauce and place back on the smoker for 1 hour.
Remove from smoker, brush with sauce again and serve.