Step 1

Make the pork: Trim off any large pieces of fat from the surface of the pork. Sprinkle the salt, pepper, and oregano evenly over all sides of the pork, then rub the seasonings into the meat. Place in the crock of a 6-quart or larger slow cooker.

Step 2

Place the maple syrup and mustard in a small bowl and whisk to combine. Pour over the pork, then turn the pork so that all sides are coated in the mixture. Pour the broth or water, tamari or soy sauce, and vinegar around, but not on top of, the pork. Scatter the onion pieces and garlic cloves around the pork. Cover and refrigerate the pork in the crock overnight.

Step 3

Place the crock in the slow cooker and cook on the LOW setting until the meat can be easily shredded, 8 to 10 hours. Transfer the pork to a cutting board. Pour the cooking liquid through a fine-mesh strainer into a measuring cup and discard the solids. Skim the fat from the surface of the cooking liquid.

Step 4

When it is cool enough to handle, use 2 forks or your fingers to shred the meat into bite-sized pieces. Discard any large pieces of fat. Transfer the pork back to the slow cooker. Add some of the cooking liquid until moist but not wet and toss to combine. Reserve the rest of the cooking liquid for storing leftovers.

Step 5

Make the sauce: Place all of the sauce ingredients in a small bowl and whisk to combine. Pile the pulled pork onto buns, drizzle with some sauce, and top with pickled onions.