Juicy beef, caramelized onions, and melted cheese layered between grilled rye or sourdough bread slices.
# 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 Prepare:
01 - Melt 2 tbsp butter in a large skillet over medium-low heat. Add sliced onions and sugar, cooking while stirring frequently until deeply golden and caramelized, about 20 to 25 minutes.
02 - Season ground beef with salt and pepper, then form into 4 thin oval patties matching the size and shape of the bread slices.
03 - Heat a separate skillet or grill pan over medium-high heat and cook patties 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 opposite side.
05 - On 4 bread slices (unbuttered side up), layer one slice of cheese, a cooked beef patty, a generous portion of caramelized onions, and another cheese slice. Top with remaining bread slices, buttered side facing out.
06 - Heat a clean skillet or griddle over medium heat. Cook sandwiches 2 to 3 minutes per side, pressing gently until bread is golden and cheese melts.
07 - Remove sandwiches from heat, let rest for 1 to 2 minutes, slice in half, and serve hot.