# What You Need:
→ Beef Patties
01 - 1.1 lbs ground beef (80/20 blend recommended)
02 - 1/2 teaspoon salt
03 - 1/2 teaspoon black pepper
→ Caramelized Onions
04 - 2 large yellow onions, thinly sliced
05 - 2 tablespoons unsalted butter
06 - 1 teaspoon sugar
→ Sandwich Assembly
07 - 8 slices rye bread or sourdough
08 - 8 slices Swiss cheese (or American cheese)
09 - 4 tablespoons unsalted butter, softened
→ Optional Condiments
10 - 1 tablespoon Dijon mustard
11 - 1 tablespoon mayonnaise
# How to Make It:
01 - Melt 2 tablespoons butter in a large skillet over medium-low heat. Add sliced onions and sugar, stirring frequently until deeply golden and caramelized, approximately 20-25 minutes. Remove from heat and set aside.
02 - While onions caramelize, combine ground beef with salt and black pepper. Form into 4 thin oval patties, matching the approximate dimensions of your bread slices.
03 - Heat a separate skillet or grill pan over medium-high heat. Sear patties for 2-3 minutes per side until well-browned and cooked through. Transfer to a plate.
04 - Butter one side of each bread slice. Optionally, spread Dijon mustard or mayonnaise on the unbuttered interior sides for added flavor.
05 - On 4 buttered slices (unbuttered side up), layer 1 cheese slice, cooked patty, generous portion of caramelized onions, and a second cheese slice. Top with remaining bread, buttered side facing outward.
06 - Heat a clean skillet or griddle over medium heat. Grill sandwiches for 2-3 minutes per side, applying gentle pressure, until bread achieves golden-brown color and cheese melts completely.
07 - Allow sandwiches to rest for 1-2 minutes before slicing diagonally. Serve immediately while hot.
