Trim fat from pork loin, pat dry. Stab all over with fork. Sprinkle with salt and pepper. If desired, brown pork roast on all sides in a large skillet or Dutch oven.
In a small bowl, combine brown sugar, mustard and vinegar. Rub all over the pork loin.
Put in large slow cooker with garlic cloves and 1/2 cup water. Cook on low for 7-9 hours.
for the glaze:
In a medium saucepan, whisk all ingredients together. Bring to a boil over medium-high heat, reduce to a simmer (medium-low heat), and simmer until thickened (10-15 minutes). Stir occasionally.
Shred pork from slow cooker. I use my stand mixer/paddle attachment! You can also use two forks. Drizzle glaze over pork and top with sesame seeds (optional). Alternatively, slice the pork and serve with a drizzle of glaze.
Make ahead tip: If desired, make a half batch of glaze. Shred all the pork, serve half of it and put half of it in the freezer for future use.