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–+ servings
Smashburger with brie and caramelized onions
Ella Cooks

Smash Burger Sliders with Brie & Caramelized Onions

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Smash burgers are already the GOAT of fast, flavorful cooking but imagine taking that crispy, beefy brilliance and dressing it up with creamy brie and golden, jammy caramelized onions. Welcome to the gourmet burger you can make at home in under 30 minutes
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Prep Time 15 minutes
Cook Time 20 minutes
Servings: 4 Sliders
Course: Main Course
Calories: 28
Ingredients Method Nutrition Notes

Ingredients
  

Ingredients
For the Patties
  • 400 g about 14 oz ground beef (80/20 or higher fat for best results)
  • Salt and freshly cracked black pepper
  • 1 tsp garlic powder optional
  • 1 tsp Worcestershire sauce optional
  • Neutral oil or butter for frying
For the Caramelized Onions
  • 1 large yellow onion thinly sliced
  • 1 tbsp butter
  • 1 tsp olive oil
  • Pinch of salt
  • Optional: ½ tsp sugar for quicker caramelizing
  • Optional: splash of balsamic or white wine vinegar at the end
For Assembling
  • 4-6 slices brie cheese rind on or off
  • 4 slider buns or mini brioche buns
  • Butter for toasting buns
  • Optional extras: arugula Dijon mustard, aioli, crispy shallots

Method
 

Step 1: Caramelize the Onions
  1. Heat butter and olive oil in a nonstick skillet over medium-low heat.
  2. Add sliced onions and a pinch of salt. Stir to coat.
  3. Cook low and slow for 15–20 minutes, stirring every few minutes, until onions are soft, golden brown, and jammy.
  4. Optional: Stir in a splash of balsamic vinegar or a pinch of sugar for extra depth.
  5. Set aside and keep warm.
Step 2: Prep the Patties
  1. Divide your ground beef into 4 equal balls (about 100g or 3.5 oz each).
  2. Keep them loose — don’t pack tightly. This helps with that crisp smash.
  3. Season lightly with salt, pepper, and garlic powder if using.
Step 3: Smash & Sear
  1. Heat a heavy-bottomed skillet or cast iron pan until very hot — almost smoking.
  2. Add a little oil and place 1–2 balls of beef in the pan (don’t overcrowd).
  3. Immediately smash them flat with a spatula or burger press (use parchment paper between spatula and meat to prevent sticking).
  4. Cook undisturbed for 2–3 minutes, until the edges are deeply browned and crisp.
  5. Flip, top each patty with a slice of brie, and cook another 1–2 minutes until cheese starts to melt.
  6. Remove from pan and repeat with remaining patties.
Step 4: Toast the Buns
  1. Wipe the skillet clean and melt a little butter.
  2. Toast the cut sides of the slider buns until golden and crisp.
Step 5: Assemble the Sliders
  1. Spread Dijon mustard or aioli on bottom buns (optional but delicious).
  2. Place brie-topped patty on each bun.
  3. Add a scoop of caramelized onions on top.
  4. Optionally layer with arugula or crispy shallots.
  5. Crown with the top bun and secure with a skewer if needed.
  6. Bonus move: Brush the tops of the buns with melted butter and a pinch of sea salt before serving.

Nutrition

Calories: 28kcalCarbohydrates: 480gProtein: 22gFat: 28gSodium: 500mg

Notes

Serving Suggestions

  • Serve with:
    • Skinny fries or sweet potato wedges
    • Arugula salad with lemon vinaigrette
    • Pickles or slaw on the side
  • Make it a board! Lay out sliders on a platter with extra onions, sauces, and napkins — they’re messy in the best way.

Storage & Reheating

  • Caramelized onions can be made ahead and refrigerated for up to 5 days.
  • Cooked patties keep for 2–3 days in the fridge; reheat in a pan or low oven.
  • Assembled sliders are best fresh but can be reheated (open-faced) in a 160°C (325°F) oven for 10 minutes.

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