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French Onion Beef Sliders Recipe
Ben Carraoli

French Onion Beef Sliders Recipe

I just made these French Onion Beef Sliders and I have to tell you — they disappeared faster than I expected. Picture sweet, slow-cooked onions mingling with seasoned ground beef, all tucked into soft slider buns and smothered in melty cheese.
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Prep Time 20 minutes
Cook Time 1 hour
Ingredients Method Notes

Ingredients
  

  • 2 large sweet onions thinly sliced — using sweet onions helps caramelize nicely without becoming too bitter.
  • 2 pounds ground beef — the base protein; leaner or fattier works but moderate fat gives better flavor.
  • 2 tablespoons beef base such as Better Than Bouillon, divided — this concentrated flavor brings savory depth without using too much liquid.
  • 1 tablespoon Worcestershire sauce divided — helps boost the umami taste and ties together the beef and onion flavor.
  • Kosher salt and freshly ground black pepper to taste — simple seasoning to enhance all the other flavors.
  • 24 slider buns — soft small buns are ideal to make these true “sliders.” )
  • 12 –16 ounces Gruyère or Swiss cheese shredded — this cheese melts beautifully and pairs excellently with the savory beef and onions.
  • 2 tablespoons sesame seeds — sprinkled on top for a little crunch and visual appeal.
  • 1 tablespoon fresh thyme — adds a slight herbaceous note that complements the beef.
  • 1 teaspoon onion powder — intensifies that onion-flavor throughout.
  • 1 teaspoon garlic powder — for a subtle garlicky background taste.

Method
 

  1. First, melt 2 tablespoons of butter in your skillet over medium heat, then add the sliced sweet onions. Reduce the heat to medium-low and cook the onions slowly, stirring occasionally, for about 25–30 minutes until they turn golden and slightly sweet. This low-and-slow approach is key for deep, rich caramelization.
  2. While the onions are cooking, combine the ground beef in a bowl with half of the beef base and half of the Worcestershire sauce. Season with kosher salt and black pepper. Then add this meat mixture to the skillet with the onions, turn the heat up to medium-high, and break the beef up as you brown it, making sure it mixes well with the onions. When fully cooked, drain off any excess grease.
  3. Preheat your oven to 350°F (175°C). Lightly grease your baking sheet. Separate the tops and bottoms of the buns, and pack the bottom halves snugly on your sheet. Spread the beef-and-onion mixture evenly over the bottoms, then sprinkle the shredded Gruyère (or Swiss) cheese on top. Close each slider by placing the bun tops back on.
  4. In a microwave-safe bowl (or over low heat), melt the remaining 6 tablespoons of butter with the rest of the beef base and the remaining 1/2 tablespoon of Worcestershire sauce. Use your pastry brush to paint this flavorful glaze over the top buns. Then sprinkle sesame seeds, fresh thyme, onion powder, and garlic powder evenly over the glazed tops. Bake for about 20 minutes, until the cheese has melted and the tops are lightly browned.

Notes

  • I found that stirring the onions gently and patiently while they cook makes all the difference: don’t rush them, or they’ll burn.
  • I like to refresh the pan with a splash of water if the onions are drying out; it helps lift the caramelized bits.
  • I used freshly shredded cheese instead of pre-shredded — it melts more smoothly and tastes better.
  • While brushing on the butter-bouillon glaze, I made sure to brush over every nook of the top buns, so each slider has that savory, buttery crust.
  • I let the baked sliders rest for a minute after coming out of the oven, just so the cheese sets a little (makes them easier to pick up).