Prepare the Pork:
Rub the pork tenderloin thoroughly with stone-ground mustard.
In a separate bowl, combine the thyme, minced garlic, minced onion, brown sugar, black pepper, celery seed, and Worcestershire sauce.
Season the mustard-coated pork tenderloin evenly with the dry ingredient mixture.
Pour water into a sheet pan and place the seasoned pork tenderloin in the pan.
Cover the pork tenderloin with barbecue sauce, ensuring it's well coated. Distribute the remaining minced garlic and onion around the pork in the pan.
Place the sheet pan in a preheated oven at 375°F (190°C) and cook for 2 hour and 20 minutes, or until the pork is tender.
Prepare the Broccoli Slaw:
In a bowl, combine the grated and sliced broccoli stems, olive oil, red wine vinegar, crushed red pepper flakes, and a pinch of salt.
Massage the broccoli slaw with your hand till softened slightly then set aside to allow the flavors to meld.
Assemble the Sliders:
Split the slider buns and lightly butter the cut sides.
Heat a griddle or pan over medium heat and toast the buttered sides of the buns until lightly golden and warm.
Once the pork is cooked and tender, shred it using two forks. Toss the shredded pork in the pan juices , adding more barbecue sauce if desired to reach your preferred consistency.
To assemble each slider, place a portion of the corn mixture on the bottom bun. Top with a generous amount of the shredded pork, followed by a layer of the broccoli slaw. Place the top bun over the slaw to finish.