Special equipment: a 3- to 4-quart slow cooker
Heat a large cast-iron skillet over medium-high heat.
Rub the oil completely over the pork and season with the salt, pepper and cayenne. Brown the pork shoulder in the skillet on all sides; this will take about 10 minutes. Remove from the skillet and allow to cool slightly before rubbing with the mustard, then coating with the brown sugar.
Place the pork in a 3- to 4-quart slow cooker, then add the soda and liquid smoke. Cover and cook on low for 7 to 8 hours. When it is done, the pork will feel extremely tender when prodded.
Remove the pork from the slow cooker, then shred the meat using 2 forks and pull off the bone. Mix the meat with any remaining cooking liquid from the slow cooker. Serve with sandwich buns and toppings of your choice.
Recipe courtesy of Adrian Davila