French Onion Beef Sliders are an easy way to feed a crowd – or just your own family. Buttery slider buns, caramelized onions, melty cheese and savory ground beef make these sliders so satisfying for a special event or a weeknight dinner. These can be made a day ahead, then popped into the oven for 20 minutes, making this a no-brainer for a quick entrée.
In a large skillet over medium-low heat, melt the butter. Add the onions, ½ teaspoon of the salt and the sugar. Cook, stirring occasionally, until soft and caramelized, about 35 – 40 minutes.Meanwhile, in a separate skillet over medium-high heat, brown the ground beef, breaking up with a spoon, until no longer pink, about 7 – 9 minutes. Stir in the garlic and thyme; cook for 1 – 2 minutes more. Off the heat, stir in beef base, Worcestershire sauce, mustard, remaining 1 teaspoon salt and black pepper.

Place the bottoms of the slider buns on the baking sheet. Evenly distribute the onions, then the beef. Layer cheese slices on top, then the slider top buns.In a small bowl, whisk together the butter, beef base, Worcestershire sauce, onion powder and garlic powder just until melted. Use a pastry brush to brush mixture on the tops of the sliders.Sprinkle sesame seeds and remaining 1 tablespoon thyme leaves on top.Bake for 20 – 25 minutes, until tops are golden brown and cheese is melted. Serve immediately.

French Onion Beef Sliders
Makes 24 sliders

2 tablespoons unsalted butter
2 large sweet onions, sliced
1 1/2 teaspoons kosher salt, divided
1 teaspoon sugar
2 pounds ground beef
2 cloves garlic, minced
½ teaspoon thyme leaves
1 tablespoon beef or chicken base (Better Than Bouillon)
1 ½ tablespoons Worcestershire sauce
1 tablespoon Dijon mustard
½ teaspoon ground black pepper
24 slider buns
16 ounces sliced Swiss cheese

Glaze:
6 tablespoons unsalted butter, melted
1 tablespoon beef or chicken base (such as Better than Bouillon)
1 ½ teaspoons Worcestershire sauce
¾ teaspoon onion powder
¾ teaspoon garlic powder
1 ½ tablespoons sesame seeds
1 tablespoon fresh thyme leaves

In a large skillet over medium-low heat, melt the butter. Add the onions, ½ teaspoon of the salt and the sugar. Cook, stirring occasionally, until soft and caramelized, about 35 – 40 minutes.

Meanwhile, in a separate skillet over medium-high heat, brown the ground beef, breaking up with a spoon, until no longer pink, about 7 – 9 minutes. Stir in the garlic and thyme; cook for 1 – 2 minutes more. Off the heat, stir in beef base, Worcestershire sauce, mustard, remaining 1 teaspoon salt and black pepper.

Preheat the oven to 350°F. Line a rimmed baking sheet with foil.

Place the bottoms of the slider buns on the baking sheet. Evenly distribute the onions, then the beef. Layer cheese slices on top, then the slider top buns.

*Make ahead: Sliders can be made up to a day ahead and refrigerated up to this point. When ready to serve, continue on with the remaining instructions.

In a small bowl, whisk together the butter, beef base, Worcestershire sauce, onion powder and garlic powder just until melted. Use a pastry brush to brush mixture on the tops of the sliders. Sprinkle sesame seeds and remaining 1 tablespoon thyme leaves on top.

Bake for 20 – 25 minutes, until tops are golden brown and cheese is melted. Serve immediately.