Ingredients:
- 5 tablespoons butter (divided)
- 1 large onion (thinly sliced)
- 2 sprigs (plus ¼ teaspoon) fresh thyme
- Kosher salt
- Freshly ground black pepper
- 12 slider buns (halved)
- 1 pound thinly sliced deli roast beef
- 12 slices provolone cheese
- ¼ teaspoon garlic powder
- 1 tablespoon clove garlic (minced)
- 1½ cups beef broth
- 1 tablespoon Worcestershire sauce
Directions
Preheat oven to 350° F.
In a large skillet over medium-high heat, melt 2 tablespoons butter. Add onion and thyme sprigs and season with salt and pepper. Cook, stirring occasionally, until caramelized, about 15 minutes. Discard thyme.
Place bottom halves of slider buns on a large baking sheet and top with roast beef, provolone cheese, caramelized onions, and slider bun tops.
Melt 2 tablespoons butter and brush on top of buns. Sprinkle with garlic powder, coarse salt, and parsley and bake until cheese is melty and sliders are warmed through, 10-15 minutes.
Meanwhile, add remaining 1 tablespoon butter to same skillet and melt over medium heat. Add garlic and cook until fragrant, 1 minute, then add beef broth, Worcestershire, and thyme and season with salt and pepper. Simmer until slightly reduced, 10 minutes.
Serve sliders with au jus for dipping.