Ingredients
Mayonnaise Mixture
- 4 tablespoons salted butter, softened
- 4 tablespoons mayonnaise
Beef Patties
- 1 pound 80/20 ground beef
- 2 teaspoons onion powder
- 2 teaspoons garlic powder
- 1½ teaspoons kosher salt, divided
- ½ teaspoon freshly cracked black pepper
- 2 teaspoons Worcestershire sauce
Sandwich Assembly
- 8 slices sourdough bread
- 8 slices Swiss cheese
- 1½ cups caramelized onions
Instructions
- Make mayonnaise mixture: In a small bowl, combine the softened butter and mayonnaise until the mixture is smooth and well blended. Set aside.
- Make the patties: In a medium bowl, mix the ground beef with onion powder, garlic powder, 1 teaspoon kosher salt, freshly cracked black pepper, and Worcestershire sauce until just combined. Divide the mixture into 4 equal portions and shape each into thin patties roughly the size and shape of the bread slices. Sprinkle the patties with the remaining ½ teaspoon of salt.
- Cook the patties: Heat a skillet over medium heat. Cook the patties in batches for 3 to 4 minutes per side until they are no longer pink in the center. Transfer cooked patties to a plate.
- Spread the mayonnaise mixture: Spread one side of each slice of sourdough bread evenly with one tablespoon of the mayonnaise-butter mixture.
- Assemble the sandwiches: Wipe out the skillet and reduce the heat to medium-low. On the unspread side of half the bread slices, layer a slice of Swiss cheese, a cooked beef patty, and evenly distributed caramelized onions. Top the onions with another slice of Swiss cheese, then cover with the remaining slices of bread, mayonnaise side down.
- Cook the sandwiches: Place the assembled sandwiches in the skillet. Cook for 4 to 5 minutes per side until the bread is golden brown and crispy and the cheese inside has melted. Once cooked, cut each sandwich in half and serve immediately.
Notes
- For best results, use freshly caramelized onions prepared in advance or store-bought high-quality caramelized onions.
- Using 80/20 ground beef ensures juiciness and flavor balance for the patties.
- If you prefer, Swiss cheese can be substituted with cheddar or another melty cheese of your choice.
- Make sure to cook the patties thoroughly but avoid pressing them to keep them juicy.
- Butter in the mayonnaise mixture helps to get the bread extra crispy and flavorful when grilled.
- Prep Time: 10 minutes
- Cook Time: 20 minutes
- Category: Sandwich
- Method: Frying
- Cuisine: American
