Combine the gravy and turkey in a medium saucepan and set over medium heat. Cook, stirring occasionally, until the gravy is hot and bubbling, 3 to 5 minutes. Turn off the heat, cover and set aside.
Put a rack in the center of the oven and preheat the broiler.
Split the attached dinner rolls in half horizontally, keeping them attached. Put the top and bottom halves cut-side up on a baking sheet. Cover the bottom half with the stuffing. Broil until toasted, 1 to 3 minutes.
Preheat the oven to 400 degrees F.
Spread the cut side of the roll tops with cranberry sauce. Cover the stuffing with mashed potatoes, then use the back of a small spoon to make 12 wells (1 for each slider) in the potatoes. Spoon the turkey and gravy into the wells (it will spill over the wells but this is okay) then cover with overlapping slices of provolone. Cover with the roll tops, then brush the tops with the melted butter. Sprinkle with flaky sea salt.
Bake until the bread is toasted and the cheese is melted, 10 to 12 minutes. Serve immediately.
