Leave the slider buns intact, and slice them in half lengthwise. Place the bottom half of the buns into a 9 x 13-inch baking dish.
12 slider buns
Lay the cheese slices over the buns, then top with the onions and sliced roast beef. Place the tops of the buns onto the sliders. Set aside.
8 ounces provolone cheese, 1 pound roast beef, ½ cup white onions
Sauce:
In a small saucepan over low heat, melt the butter. Stir in the Worcestershire sauce, mustard, garlic powder, onion powder, and seasoned salt. Pour the mixture over the sliders.
½ cup unsalted butter, 1 tablespoon Worcestershire sauce, 1 teaspoon Dijon mustard, ½ teaspoon garlic powder, ¼ teaspoon onion powder, ¼ teaspoon seasoned salt
Bake uncovered for 10 to 15 minutes until the cheese is melted and the tops are golden brown.
Use a sharp knife to separate the sliders. Serve hot with a side of au jus.
See post for storage recommendations.
Notes
*The mustard sauce is intended to be poured over the sliders and baked. It's not used as a dipping sauce.*The au jus in the photos is store bought, but a homemade version would taste amazing with this recipe.*The calories listed are an approximation based on the ingredients in the recipe card and a serving size of 1 slider. Actual calories will vary.*For more information, tips, and answers to frequently asked questions, please refer to the post.