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French Onion Smashburgers with Gruyère

French Onion Smashburgers with Gruyère

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Prep Time 15 minutes
Cook Time 45 minutes
Total Time 1 hour
Servings: 4
Course: Main Course
Cuisine: American
Calories: 620
Ingredients Method Notes

Ingredients
  

  • Caramelized Onions:
  • 3 large yellow onions thinly sliced
  • 2 tbsp unsalted butter
  • 1 tbsp olive oil
  • ½ tsp salt
  • 1 tsp sugar optional
  • 2 tbsp beef broth
  • Burgers:
  • 1½ lbs 80/20 ground beef
  • Salt & pepper
  • 4 brioche buns
  • 4 slices Gruyère cheese
  • 1 tbsp Dijon mustard

Method
 

  1. Heat butter and olive oil in skillet over medium-low heat.
  2. Add onions and salt. Cook 30–40 minutes, stirring occasionally.
  3. Add beef broth and cook until absorbed. Set aside.
  4. Preheat cast iron skillet to high heat.
  5. Form beef into 4 loose balls.
  6. Place ball in skillet and smash firmly with spatula using parchment paper.
  7. Season with salt and pepper.
  8. Cook 2–3 minutes until browned. Flip once.
  9. Add Gruyère and cook 1–2 minutes until melted.
  10. Toast brioche buns.
  11. Assemble with Dijon, burger, onions, and top bun.

Notes

  • Use high heat for proper crust formation.
  • Do not overwork ground beef.
  • Caramelize onions slowly for best flavor.
  • Toast buns to prevent sogginess.