Step 2

Sprinkle beef all over with garlic powder and black pepper; place in a 5- to 6-quart slow cooker.

Step 3

Remove 2 tablespoons liquid from pepperoncini peppers and set aside. Pour remaining 6 tablespoons pepperoncini liquid over beef in cooker; top with pepperoncini peppers. Cover and cook on low until beef is very tender, about 8 hours.

Step 4

Remove beef from cooker, and let stand about 10 minutes. Shred beef, and toss with 1/4 cup cooking liquid from the slow cooker.

Step 5

Place cabbage, carrot, scallions, olive oil, mustard, and reserved 2 tablespoons pepperoncini liquid in a medium bowl; toss to coat. Divide beef among bottom halves of slider buns; top with slaw, and cover with bun tops.