Preheat oven to 350 degrees.

Butter the bottom and sides of an 8 x 11 or 9 x 13 baking dish with the softened butter.

Slice the package of rolls in half, separating the tops from the bottoms.

Place the bottom half of the rolls in the baking dish and begin assembling in this order: 6 slices of provolone cheese, roast beef (all of it), french fried onions, and the remaining 6 slices of provolone cheese. Finally, top with the other half of the Hawaiian rolls.

In a small microwaveable bowl, add the butter, 1 tbsp of au jus seasoning mix, ½ of the sesame seeds, and the onion powder.

Heat in the microwave until the butter has melted, mix well with a small whisk or spoon.

Using a brush, top the rolls evenly with the melted butter mixture. It is okay to not use all of it as long as all of the rolls are coated. I like to brush some on the sides as well if there is enough space to do so.

Sprinkle the remaining sesame seeds over the tops of the rolls.

Bake the sliders for 18-20 minutes or until the tops are golden brown and the cheese is melted.

Remove and cut the sliders into 12 individual servings. Serve warm.

While the sliders are baking, use the remaining au jus seasoning mix to make a dipping sauce. Place the mix in a small saucepan with 1½ - 2 cups of water, bring to a boil, and reduce heat to a simmer for approximately 5 minutes while the sauce thickens, stirring occasionally.

Serve warm with sliders in small dipping cups.