01 -
Melt 3 tablespoons unsalted butter in a large skillet over medium heat. Add the sliced onions and cook, stirring occasionally, for 12–15 minutes until soft and browned. Do not allow to burn.
02 -
Add minced fresh thyme, kosher salt, and black pepper to the caramelized onions. Stir to combine, remove from heat, and set aside.
03 -
Preheat oven to 175°C. Remove the sweet rolls from the package, keeping them intact. With a large knife, slice the rolls horizontally to create top and bottom halves. Place the bottom halves, cut side up, into an 28x18cm baking dish.
04 -
Arrange half of the provolone cheese over the bottom rolls. Distribute the sliced roast beef evenly. Top with caramelized onions, spread out evenly, and add the remaining provolone. Cover with the top roll halves.
05 -
In a small bowl, mix the melted butter with dried onion soup mix. Brush or evenly pour the mixture over the tops of the rolls.
06 -
Cover the baking dish loosely with foil, ensuring it does not touch the rolls. Bake for 25 minutes. Remove the foil and bake an additional 5 minutes until the rolls are golden brown.
07 -
While sliders bake, prepare au jus according to packet instructions using 3 cups water. Keep warm for serving.
08 -
Garnish sliders with chopped parsley if desired. Serve warm with au jus for dipping.