Ingredients:

  • 3 large yellow onions, thinly sliced (about 600g / 21 oz)
  • 2 tablespoons olive oil (30 ml)
  • 2 tablespoons unsalted butter (30g)
  • 1 teaspoon granulated sugar (5g)
  • 1/2 teaspoon salt (3g)
  • 1/4 teaspoon black pepper (1g)
  • 1/4 cup dry red wine (such as Burgundy or Merlot) (60 ml)
  • 1 tablespoon olive oil (15 ml)
  • 1 pound ground beef (80/20 blend recommended) (450g)
  • 1 teaspoon garlic powder (5g)
  • 1/2 teaspoon onion powder (3g)
  • 1/4 teaspoon dried thyme (1g)
  • 4 cups beef broth (low sodium) (950 ml)
  • 2 tablespoons Worcestershire sauce (30 ml)
  • 12 slider buns (Hawaiian rolls or similar), split
  • 4 ounces Gruyere cheese, shredded (115g)
  • 2 tablespoons melted butter, for brushing (30g)
  • Optional: fresh thyme sprigs, for garnish

Instructions:

  1. Heat olive oil and butter in a large skillet. Add sliced onions, sugar, salt, and pepper. Cook over medium-low heat, stirring occasionally, until deeply golden brown and caramelized (about 25-30 minutes). Deglaze the pan with red wine, scraping up any browned bits. Set aside.
  2. Heat olive oil in a separate skillet. Brown the ground beef over medium-high heat, breaking it up with a spoon. Drain off any excess grease.
  3. Add garlic powder, onion powder, and thyme to the beef. Stir in beef broth and Worcestershire sauce. Bring to a simmer and cook for 10 minutes, or until slightly thickened.
  4. Preheat oven to 350°F (175°C). Place slider buns on a baking sheet. Spoon the ground beef mixture evenly onto the bottom halves of the buns. Top with caramelized onions and shredded Gruyere cheese.
  5. Cover with the top halves of the buns. Brush the tops of the buns with melted butter. Bake for 10-12 minutes, or until the cheese is melted and bubbly and the buns are lightly toasted.
  6. Garnish with fresh thyme sprigs (optional) and serve immediately.