Cut the rolls in half lengthwise to turn them into buns. Place the bottom halves in the crockpot. Layer the bottom half with ham slices and Sargento® Sliced Provolone Cheese and place the top half back on.
In a bowl, mix together the butter, Worcestershire, mustard, brown sugar and onion powder. Pour sauce over sandwiches, drenching each one.
Cover and cook on high for 1 to 1.5 hours or until cheese is melted and rolls are hot. You can toast them under the broiler for a minute to get a crispier top. Run a knife between the buns to separate and serve right out of the crockpot set on warm to keep the sandwiches hot.
NOTE: You can prep these up to 24 hours in advance. Just cover tightly and refrigerate until ready to cook.