I found this recipe on Cooking Light's website. Not sure how authentic it is, but it was yummy! I used a 2 lb pork tenderloin instead of Boston Butt.
Slow Cooker Char Siu Pork
Ingredients
* 1/4 cup low-sodium soy sauce
* 1/4 cup hoisin sauce
* 3 tablespoons ketchup
* 3 tablespoons honey
* 2 teaspoons bottled minced garlic
* 2 teaspoons grated peeled fresh ginger
* 1 teaspoon dark sesame oil
* 1/2 teaspoon five-spice powder
* 2 pounds boneless Boston butt pork roast, trimmed
* 1/2 cup fat-free, less-sodium chicken broth
Preparation
Combine first 8 ingredients in a small bowl, stirring well with a whisk. Place in a large zip-top plastic bag. Add pork to bag; seal. Marinate in refrigerator at least 2 hours, turning occasionally. (Note: I marinated overnight.)
Place pork and marinade in an electric slow cooker. Cover and cook on low for 8 hours.
Remove pork from slow cooker using a slotted spoon; place on a cutting board or work surface. Cover with aluminum foil; keep warm.
Add broth to sauce in slow cooker. Cover and cook on low for 30 minutes or until sauce thickens. Shred pork with 2 forks; serve with sauce.