In a large skillet over medium heat, melt 3 Tablespoons unsalted butter. Add 1 medium onion, thinly sliced and coat in the butter. Cook, stirring occasionally, for about 12-15 minutes until the onions are soft and browned but not burnt.
Add 2 teaspoon fresh thyme, minced, ¼ teaspoon kosher salt and ¼ teaspoon black pepper stir to combine, take off the heat.
Preheat the oven to 350°F.
Take the 12 Hawaiian sweet rolls out of the package, leaving the rolls intact. Take a large knife and slice the rolls across so you have the tops and bottom separated. Place the bottom, cut side up into an 11x7-inch (or 9x13-inch) baking dish.
Top the bottom half of the rolls with HALF of the 10 slices provolone cheese and all 14 ounces sliced deli roast beef. Set aside.
Top the roast beef layer with the cooked onions, spreading them out evenly.
Add the remaining sliced provolone cheese, then place the top half of the rolls on top.
In a small bowl stir together ½ cup unsalted butter, melted and 1 ½ Tablespoons dried onion soup mix. I like to brush this mixture on top of the rolls to make sure it’s evenly distributed but you can just pour the butter sauce on top.
Cover the baking dish loosely with foil, you want to make sure the foil is not touching the tops of the rolls and bake for 25 minutes. Take the foil off and bake an additional 5 minutes to brown the rolls.
While the rolls are baking, prepare the 1 packet au jus gravy mix per the package directions with the 3 cups water.
Serve the rolls topped with a sprinkling of fresh chopped parsley (optional) with the prepared au jus on the side for dipping.
Video
Notes
You can substitute the deli roast beef with an leftover pot roast.
Use any of your favorite slider buns for this recipe.
The au jus is optional but we really love dipping these in it.
Provolone can be swapped for mozzarella or swiss cheeses if you'd like.