2) Add the garlic, onion, chilli powder, coriander seeds and cumin to the drippings in the skillet and stir until fragrant, about 1 minute. Add the vinegar and boil until it's almost gone, scraping the bottom of the pan with a wooden spoon. Stir in the water and pour the mixture over the brisket.
3) Crush the tomatoes through your fingers into the slow cooker; add the tomato juices, chipotles, bay leaves and treacle. Cover the cooker, set it on LOW, and cook the brisket until it pulls apart easily with a fork, about 8 hours.
4) To serve, leave the meat in the slow cooker and use 2 forks to pull it apart and stir it evenly into the sauce; season with salt and pepper, to taste. Remove and discard the bay leaves. Pile the meat on the sandwich buns and serve with jalapenos.
Cook's Note: This is also great rolled up in tortillas.