Description
These Buttery Roast Beef Sliders with Caramelized Onions are a deliciously savory treat featuring tender roast beef layered with melty cheese, sweet caramelized onions, and a homemade garlic aioli, all nestled inside soft slider buns. Topped with a flavorful garlic butter sauce and served with rich au jus for dipping, these sliders are perfect for gatherings, game days, or a comforting meal at home.
Ingredients
Scale
Caramelized Onions
- 2 tablespoons unsalted butter
- 1 tablespoon olive oil
- 3 large yellow onions, thinly sliced
- ½ teaspoon kosher salt
- 1 teaspoon brown sugar
- 2 tablespoons beef broth
Homemade Garlic Aioli
- 1 large egg yolk, room temperature
- 1 teaspoon Dijon mustard
- 1 garlic clove, finely grated or minced
- 1 tablespoon fresh lemon juice
- ½ cup light olive oil or neutral oil
- Kosher salt, to taste
Au Jus Sauce
- ¼ cup unsalted butter
- 1 tablespoon Better than Bouillon Beef Base
- 2 cups beef broth
- 2 teaspoons Worcestershire sauce
Roast Beef Sliders
- 12 slider buns, sliced in half (Hawaiian rolls preferred)
- ¼ cup homemade garlic aioli or mayonnaise
- ½ pound deli roast beef, thinly sliced
- 12 slices melty cheese (provolone, Swiss, or muenster)
- ½ cup shredded mozzarella cheese
- 2 cups caramelized onions
Garlic Butter Sauce
- 6 tablespoons unsalted butter, melted
- 1 teaspoon Worcestershire sauce
- 1 tablespoon poppy seeds
- 1 tablespoon white sesame seeds
- ½ tablespoon garlic powder
- ½ tablespoon dried minced onion
- ½ teaspoon kosher salt
- Freshly cracked black pepper, to taste
Instructions
- Make the Caramelized Onions: Melt the butter and olive oil in a large skillet over medium-low heat. Add the sliced onions, sprinkle with salt and brown sugar, then cook low and slow, stirring occasionally, until the onions are soft, deep golden brown, and jammy, about 45 minutes. Stir in beef broth to deglaze the pan, then set aside.
- Make the Garlic Aioli: In a small bowl, whisk together the egg yolk, Dijon mustard, grated garlic, and lemon juice until smooth. Using an immersion blender or a whisk, slowly stream in the oil until the mixture thickens into creamy aioli. Season with salt and set aside. Alternatively, mix mayo with garlic, mustard, lemon, and salt for a quicker version.
- Prepare the Au Jus Sauce: Melt butter in a medium saucepan over medium heat. Stir in the beef base, beef broth, and Worcestershire sauce. Simmer for 20 minutes until reduced by half and slightly thickened. Keep warm.
- Toast the Bottom Buns: Preheat oven to 350°F. Slice buns horizontally without separating the halves. Place bottom halves cut-side up on a parchment-lined baking sheet. Lightly brush with melted butter or aioli and toast for 5 minutes until lightly golden.
- Assemble the Sliders: Spread a generous layer of garlic aioli over toasted bottom buns. Pile roast beef evenly in 2-3 layers. Top with slices of melty cheese, then sprinkle shredded mozzarella over the top. Spoon caramelized onions evenly across the sliders.
- Add the Top Buns and Garlic Butter: Place top halves on sliders. In a small bowl, combine melted butter, Worcestershire sauce, poppy seeds, sesame seeds, garlic powder, minced onion, salt, and pepper. Generously brush on the top rolls.
- Bake the Sliders: Cover sliders loosely with foil and bake for 10 minutes. Remove foil and bake for another 10 minutes until tops are golden brown and cheese is melted.
- Serve: Slice between rolls to separate sliders. Serve warm with bowls of au jus for dipping.
Notes
- For a quicker 30-minute version, jazz up mayonnaise with aioli ingredients and bake without caramelized onions.
- Make ahead by assembling sliders up to two days in advance without onions or garlic butter; add before baking.
- Store leftovers in an airtight container for up to 3 days.
- Reheat leftovers in a 375°F oven for 10 minutes to prevent sogginess.
- Use Hawaiian slider buns for best texture and flavor.
- Better than Bouillon provides rich flavor; substitute with beef bouillon paste or concentrate if unavailable.
- Adjust seasoning in au jus and garlic butter to suit taste preferences.
Nutrition
- Serving Size: 1 slider
- Calories: 350 kcal
- Sugar: 4 g
- Sodium: 630 mg
- Fat: 22 g
- Saturated Fat: 10 g
- Unsaturated Fat: 9 g
- Trans Fat: 0 g
- Carbohydrates: 24 g
- Fiber: 2 g
- Protein: 16 g
- Cholesterol: 75 mg
