Crispy, buttery bread stuffed with juicy beef patties, melty cheese, caramelized onions, and a tangy, creamy secret sauce. A diner classic you’ll want to make over and over again!
1 lb (450g) ground beef (80/20 for juicy patties)
Salt and pepper, to taste
8 slices rye bread (or sourdough)
8 slices Swiss cheese (or cheddar if you prefer)
2 large onions, thinly sliced
2 tbsp butter (plus more for spreading on bread)
1 tbsp olive oil
1/2 cup mayonnaise
2 tbsp ketchup
1 tbsp Dijon mustard
1 tbsp sweet pickle relish
1 tsp Worcestershire sauce
1/2 tsp garlic powder
1/2 tsp paprika
In a small bowl, whisk together mayonnaise, ketchup, Dijon mustard, relish, Worcestershire sauce, garlic powder, and paprika.
Refrigerate until ready to use.
In a large skillet, heat butter and olive oil over medium heat.
Add onions and cook slowly, stirring often, until deep golden brown and caramelized (20–25 minutes).
Set aside.
Season the ground beef with salt and pepper and divide into 4 thin, oval-shaped patties (to match the bread shape).
Cook patties in a hot skillet for 3–4 minutes per side, until just cooked through.
Spread butter on one side of each bread slice.
Place 4 slices, buttered side down, on a flat surface.
Spread secret sauce on the unbuttered side.
Top with a slice of cheese, a beef patty, caramelized onions, another slice of cheese, and finally another slice of bread (buttered side out).
Cook each sandwich in a skillet or on a griddle over medium heat for 3–4 minutes per side, until the bread is golden and the cheese is melted.
Slice in half and serve hot with extra secret sauce for dipping!
Perfect with fries or a simple green salad.