Mix rub ingredients together, then rub over the entire roast.

Add 1 tbsp olive oil to a skillet and heat on medium high. Sear all sides of roast (about a minute on each side) to seal in the juices and give it color.

Place onions, garlic and jalapeno in slow cooker. Top with seared roast, then pour bottle of stout in the cooker around the roast.

Cover and cook on high for 4 hours, or on low for 8 hours. Pork should be tender enough to shred.

Remove from cooker and let cool slightly. Shred roast using two forks.

Heat remaining olive oil in a large skillet on high heat. Spread pork in pan in batches so as not to overcrowd the pan. Drizzle some of the juices from the slow cooker over the meat and let cook for a few minutes, until liquid is absorbed and meat has some crispy edges. Turn and sear briefly, then remove from pan (don't over cook or it will dry out). Repeat with the remaining batches of meat. Drizzle more juice over meat if desired.