- 5 tablespoons butter, divided
- 3 large onions, thinly sliced
- Salt and pepper
- 1/4 teaspoon ground thyme
- 1/4 cup dry sherry
- 1/2 cup beef stock or beef consomm
- 1 1/2 pounds ground chuck or sirloin
- 2 tablespoons Worcestershire sauce
- 2 tablespoons finely chopped parsley
- 2 tablespoons Dijon mustard
- 1 tablespoon EVOO Extra Virgin Olive Oil
- 8 slices good quality white bread
- 8 slices Gruyre or Swiss cheese
- Cornichons, for garnish
Melt 2 tablespoons butter in a medium skillet over medium heat. Add onions and season with salt, pepper and thyme; cook until caramel in color and very soft, 25-30 minutes. Add sherry and stock.
Combine beef with Worcestershire, parsley, Dijon, salt and pepper; form 4 patties. Heat a griddle or cast-iron pan over medium-high heat, drizzle with oil and cook patties 7-8 minutes, turning once. Clean griddle and return to stovetop over medium heat.
Butter bread slices on one side and build patty melts with butter sides out, stacking bread, cheese, onions, a patty, more onions, cheese and bread.
Grill sandwiches until crispy and golden, and the cheese has melted. Serve the patty melts with a simple watercress salad and cornichons alongside, pass extra mustard at the table.