# Ingredient List:
→ Beef Patties
01 - 1.1 lbs ground beef, 80/20 blend
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 Assembly
07 - 8 slices rye bread or sourdough
08 - 8 slices Swiss cheese or American cheese
09 - 4 tbsp unsalted butter, softened
→ Optional Condiments
10 - 1 tbsp Dijon mustard
11 - 1 tbsp mayonnaise
# How-To Steps:
01 - Melt 2 tbsp butter in a large skillet over medium-low heat. Add sliced onions and sugar. Cook, stirring frequently, until onions are deeply golden and caramelized, about 20–25 minutes. Remove from heat and set aside.
02 - While onions caramelize, season ground beef with salt and pepper. Shape into 4 thin oval patties, matching the size and shape of your bread slices.
03 - Heat a separate skillet or grill pan over medium-high heat. Cook patties for 2–3 minutes per side until well-browned and cooked through. Remove from heat.
04 - Lay out all 8 bread slices. Spread a thin layer of softened butter on one side of each slice. If desired, spread Dijon mustard or mayonnaise on the unbuttered sides.
05 - On 4 buttered slices, layer: 1 slice cheese, one cooked patty, generous 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. Cook sandwiches for 2–3 minutes per side, pressing gently with a spatula, until bread is golden brown and cheese is fully melted.
07 - Transfer sandwiches to a cutting board. Let rest for 1–2 minutes, then slice diagonally and serve immediately.