Ingredients:

  • 2 medium yellow onions, thinly sliced (approx. 300g / 10.5 oz)
  • 2 tablespoons unsalted butter (28g / 1 oz)
  • 1 tablespoon olive oil (15 ml / 0.5 fl oz)
  • 1/2 teaspoon granulated sugar (2.5g / 0.09 oz)
  • 1/4 teaspoon salt (1.5g / 0.05 oz)
  • 1/4 teaspoon freshly ground black pepper (0.5g / 0.01 oz)
  • 1 pound ground beef (80/20 blend recommended) (454g / 16 oz)
  • 1 teaspoon Worcestershire sauce (5 ml / 0.17 fl oz)
  • 1/2 teaspoon garlic powder (2.5g / 0.09 oz)
  • 1/4 teaspoon salt (1.5g / 0.05 oz)
  • 1/4 teaspoon freshly ground black pepper (0.5g / 0.01 oz)
  • 4 slices rye bread
  • 4 tablespoons unsalted butter, softened (56g / 2 oz)
  • 4 slices Swiss cheese

Instructions:

  1. Melt butter and olive oil in a skillet over medium heat. Add onions, sugar, salt, and pepper. Cook, stirring occasionally, until onions are deeply golden brown and softened (about 20-25 minutes).
  2. In a small bowl, combine ground beef, Worcestershire sauce, garlic powder, salt, and pepper. Gently mix until just combined. Form into two patties, slightly larger than the bread slices.
  3. Heat the skillet over medium-high heat. Cook patties for 3-4 minutes per side, or until cooked to your desired doneness (medium-rare to medium-well is recommended).
  4. Spread softened butter on one side of each slice of rye bread. Place two slices of bread, butter-side down, in the skillet over medium heat.
  5. Top each slice of bread with one slice of Swiss cheese, half of the caramelized onions, one beef patty, and another slice of Swiss cheese. Top with the remaining bread slices, butter-side up.
  6. Cook for 3-4 minutes per side, or until the bread is golden brown and the cheese is melted and gooey. Gently press down on the sandwiches with a spatula to help them cook evenly.
  7. Cut each patty melt in half and serve immediately.