Juicy beef, sweet caramelized onions, and melted cheese layered between buttery rye or sourdough bread.
# What You’ll Need:
→ Beef
01 - 1.1 lbs ground beef (80/20 blend recommended)
02 - 1/2 tsp salt
03 - 1/2 tsp black pepper
→ 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
10 - 1 tbsp Dijon mustard
11 - 1 tbsp mayonnaise
# How-To:
01 - Melt 2 tablespoons unsalted butter in a large skillet over medium-low heat. Add thinly sliced onions and sugar. Cook, stirring frequently, until onions turn deeply golden and caramelized, approximately 20 to 25 minutes. Remove from heat and set aside.
02 - Season ground beef with salt and black pepper. Form into 4 thin oval patties matching the size of the bread slices.
03 - Over medium-high heat, cook patties in a skillet or grill pan for 2 to 3 minutes per side until browned and just cooked through. Remove from heat.
04 - Lay out 8 slices of bread. Spread softened butter on one side of each slice. Optionally, spread Dijon mustard or mayonnaise on the unbuttered side. On 4 slices (unbuttered side up), layer Swiss cheese slice, beef patty, a generous spoonful of caramelized onions, and another slice of cheese. Top with remaining bread slices, buttered side facing out.
05 - Heat a clean skillet or griddle over medium heat. Cook sandwiches 2 to 3 minutes per side, pressing gently, until the bread is golden brown and cheese has melted.
06 - Remove sandwiches from heat, let rest for 1 to 2 minutes, then slice in half and serve warm.
