Roast beef sliders piled high with cheese, caramelized onions and garlic bread buns! A quick 30 minutes dish that you will be making over and over. Perfect for entertaining as appetizers or a main course for a weeknight dinner, these are always a fan favorite and crowd pleaser.
For the caramelized onions, in a large frying pan on medium heat, melt the 3 tablespoons of butter. Add the onions and cook on low for about 10-12 minutes until just starting to brown, stirring often.
Once the onions start to brown, add in the minced garlic and rosemary. Continue cooking for about 5 minutes or until the onions are caramelized and golden brown in color. Remove the pan from the heat and set aside.
Line a sheet pan or baking tray with parchment paper. Place the slider buns on top and cut them through the center. Set the tops of the buns to the side.
Assemble the sliders by first layering the roast beef on the bottoms of the buns.
Then add a layer of sliced cheese on top of the roast beef. Depending on the size of the slices of cheese, add 4 – 6 slices, or more to cover the roast beef.
Evenly distribute the caramelized onions over top of the cheese.
Place the slider bun tops back on.
Prepare the garlic butter in a small bowl by mixing together the melted butter, mustard powder, garlic powder and parsley. Stir until evenly combined.
Use a brush to spread the garlic butter over top of the slider buns. Brush garlic butter on the sides of the slider buns too.
Transfer the sliders to the preheated oven and bake for about 5-8 minutes, or until the cheese has melted and the buns are toasted.
Remove the sliders from the oven and allow to cool for 2-3 minutes. You can pull the sliders apart or use a knife to slice the sliders apart. Serve and enjoy!