Trim away any large amounts of fat from pork. At Tesco we picked up 3 large chunks of meat, about 1 kilo each.
If you wish to use an onion, slice and place at the bottom of the slow cooker, place meat on top of that.
Pour the beer over the meat until about an inch from the top of the pot. Add salt to your taste, generous amounts of black pepper and garlic powder.
Cover and set to High for 1 hour, then reduce to Low for 8 hours.
At 8 hours, remove pork from pot, use two large slotted spoons as the meat will fall apart. Discard the onion and liquid. Shred the pork using two large sturdy forks and return to the slow cooker pot.
Add the BBQ sauce and Sriracha sauce, mix well and put slow cooker on low for 30 minutes to an hour. Serve on buns, and I like to use a slice of onion on mine as well.