# What You'll Need:
→ Beef Patties
01 - 1.1 lbs ground beef, 80/20 fat ratio
02 - 1/2 tsp salt
03 - 1/2 tsp black pepper
→ Caramelized Onions
04 - 2 large yellow onions, thinly sliced
05 - 2 tbsp unsalted butter
06 - 1 tsp sugar
→ Sandwich Components
07 - 8 slices rye bread or sourdough
08 - 8 slices Swiss or American cheese
09 - 4 tbsp unsalted butter, softened
10 - 1 tbsp Dijon mustard (optional)
11 - 1 tbsp mayonnaise (optional)
# How to Make It:
01 - Melt 2 tablespoons butter in a large skillet over medium-low heat. Add sliced onions and sugar. Cook stirring frequently until onions turn deep golden brown and develop a sweet, concentrated flavor, approximately 20 to 25 minutes. Remove from heat and set aside.
02 - While onions slowly caramelize, combine ground beef with salt and black pepper. Gently mix just until seasonings are evenly distributed. Shape into four thin oval patties that match the approximate dimensions of your bread slices. Avoid overworking the meat to maintain tenderness.
03 - Heat a separate skillet or grill pan over medium-high heat until hot. Place patties in the pan and cook for 2 to 3 minutes on the first side until a well-brown crust forms. Flip and continue cooking for another 2 to 3 minutes until the second side is browned and the patties are cooked through. Transfer to a plate and set aside.
04 - Lay out all eight bread slices. Spread a thin, even layer of softened butter on one side of each slice. On the unbuttered side, you may optionally spread Dijon mustard or mayonnaise for added flavor depth.
05 - Working with four buttered bread slices butter-side down, place one slice of cheese on each. Add one cooked beef patty, distribute caramelized onions evenly, then top with a second slice of cheese. Complete each sandwich with a remaining bread slice, buttered side facing outward.
06 - Heat a clean skillet or griddle over medium heat. Place assembled sandwiches in the pan and cook for 2 to 3 minutes on the first side until bread achieves golden-brown color. Flip carefully and cook the second side for an additional 2 to 3 minutes until bread is evenly toasted and cheese has completely melted.
07 - Transfer sandwiches to a cutting board and let rest for 1 to 2 minutes, allowing the cheese to set slightly. Cut each sandwich diagonally in half and serve immediately while hot and crispy.
