# What You 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
→ Caramelized 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
# How To Make It:
01 - Combine ground beef, Worcestershire sauce, garlic powder, kosher salt, and black pepper in a mixing bowl. Form into 4 equal-sized 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 salt. Cook, stirring occasionally, until onions are golden and caramelized, about 12 to 15 minutes. Remove and set aside.
03 - Increase heat to medium-high. Add beef patties to the skillet and cook until browned and cooked through, approximately 3 to 4 minutes per side. Remove and set aside.
04 - Wipe the skillet clean. Butter one side of each bread slice. Place 4 slices, buttered side down, in the skillet. Layer each with a slice of Swiss cheese, a beef patty, caramelized onions, another slice of Swiss cheese, and top with the remaining bread slice, buttered side up.
05 - Cook over medium heat until the bread is golden brown and the cheese melts, about 3 minutes per side. Press gently with a spatula to develop an even crust.
06 - Slice each sandwich in half and serve immediately while hot.
