Directions

1. In a medium saucepan over medium heat, melt the butter. Add the onion and cook, stirring occasionally, until translucent, about 5 minutes. Add the ketchup, water, lemon juice, brown sugar, mustard, Worcestershire sauce and salt and bring to a boil over high heat. Reduce to a simmer and cook for 10 minutes. Remove from the heat and set aside to cool.
2. Place the pork in a slow cooker. Reserve 1 cup of the sauce and set the remaining aside in the refrigerator. Use a meat injector to inject the 1 cup of sauce into the meat, piercing it all over 6 to 10 times (depending on your meat injector, you may need to strain the sauce first). Cover the meat and cook on low 6 to 8 hours, until the meat is very tender.
3. About 30 minutes before the meat is done, bring the remaining sauce to room temperature.
4. Serve the meat with the sauce.