Start by melting 3 tablespoons of unsalted butter in a large skillet over medium heat. Add the sliced onion, allowing it to sauté for about 12-15 minutes until beautifully browned and softened. Stir occasionally to prevent sticking and enhance the sweetness. Once done, add fresh thyme, kosher salt, and black pepper to taste, ensuring everything is well combined before removing the skillet from heat.

Preheat your oven to 350°F (175°C) while preparing the sweet rolls. This temperature will ensure your French Dip Sliders bake perfectly.

Slice the Hawaiian sweet rolls in half horizontally, placing the bottom halves in your prepared baking dish. Layer half of the provolone cheese evenly over the rolls, followed by a generous portion of deli roast beef. Top it off with the sautéed onions and the remaining cheese.

Carefully place the top halves of the slider rolls over the filled bottom halves. This will create pockets for all the tasty ingredients.

In a small bowl, mix the melted butter with the dried onion soup mix. Brush this mixture generously over the tops of the rolls.

Cover the baking dish loosely with foil and place it in the preheated oven. Bake for approximately 25 minutes, allowing the flavors to meld. Remove the foil and bake for an additional 5 minutes for a golden-brown crust.

While the sliders are baking, prepare the au jus according to package instructions, mixing water with the au jus gravy mix.

Once the sliders are out of the oven, allow them to cool slightly before cutting into individual portions. Serve warm alongside the au jus for dipping.