# What you'll need:
→ Patties
01 - 1 lb ground beef (80/20 blend recommended)
02 - 1 tsp Worcestershire sauce
03 - 1/2 tsp garlic powder
04 - 1/2 tsp kosher salt
05 - 1/4 tsp freshly ground black pepper
→ Onions
06 - 2 large yellow onions, thinly sliced
07 - 2 tbsp unsalted butter
08 - 1/4 tsp salt
→ Assembly
09 - 8 slices rye bread
10 - 8 slices Swiss cheese
11 - 4 tbsp unsalted butter, softened (for bread)
12 - Optional: 2 tbsp mayonnaise
# Method:
01 - Combine ground beef, Worcestershire sauce, garlic powder, kosher salt, and black pepper in a mixing bowl. Shape into 4 even patties slightly larger than the bread slices.
02 - Heat a cast iron skillet over medium heat. Melt 2 tablespoons of unsalted butter, add sliced onions and 1/4 teaspoon salt. Cook, stirring occasionally, until golden and caramelized, approximately 12 to 15 minutes. Remove onions and set aside.
03 - Increase skillet heat to medium-high. Add beef patties and cook 3 to 4 minutes per side until browned and cooked through. Remove from skillet and set aside.
04 - Wipe skillet clean. Butter one side of each bread slice with softened butter. Place 4 slices butter-side down in skillet. Layer each with Swiss cheese, a beef patty, caramelized onions, another slice of Swiss cheese, and top with remaining bread slices butter-side up.
05 - Cook over medium heat until bread is golden and cheese melts, about 3 minutes per side. Press gently with a spatula to ensure even crust development.
06 - Slice each patty melt in half and serve immediately while hot.
