Combine the rub ingredients in a small bowl.
Generously coat the brisket with lots of black pepper on all sides, then coat in the spice rub, massaging the spices into the meat. Cover with plastic wrap and let sit overnight in the fridge.
Pre-heat a smoker to around 250°F and set up for cooking over indirect heat by placing coals and wood chips to one side. Place the brisket on the other side and cook, fat-side up, for 4 hours.
Pull the meat off and slather with the grated onion. Using a double layer of foil, create a pouch/packet for the brisket. Add the apple juice and beer and tightly seal the foil.
Place the brisket back in the smoker for another 2 hours, adding a handful of chips and 12 or so coals. After 2 hours, open the lid and let the brisket sit in the packet for another hour.
While the brisket finishes cooking, make the Smoky BBQ Sauce and Sweet ‘n Spicy Pickles.
To make the Smoky BBQ Sauce, combine all the sauce ingredients in a small saucepot and bring to a simmer. Cook at a low bubble for 15-20 minutes. Note: This recipe makes about 1.5 cups sauce.
To make the Sweet ‘n Spicy Pickles, bring the vinegar, water, sugar and salt to a boil in a small pot. Reduce the heat to low and simmer for 5 minutes. Put the garlic, bay, chili pepper, cucumber, onion and dill in a small storage container and sprinkle in a little mustard seed, coriander seed and black peppercorn. Pour the hot brine over the pickles. Cool, cover and chill, shaking every once in a while, overnight. Note: This recipe makes about 80-100 pickles.
To serve, thinly slice the brisket on a large cutting board. Add some barbecue sauce to the meat and give everything a rough chop to combine. Assemble the sammies by placing a pile of brisket on the biscuit bottoms. Add a couple slices of pickles and replace the tops.