FRENCH ONION & ROAST BEEF GRILLED CHEESE SANDWICH RECIPE - (4.4/5)

French Onion & Roast Beef Grilled Cheese Sandwich Recipe - (4.4/5) image

Provided by á-34480

Number Of Ingredients 10

1 tablespoon olive oil
1 small onion, sliced
1 teaspoon thyme leaves
Kosher salt
Pepper
4 slices (1/2-inch-thick) rye bread
1 tablespoon unsalted butter or olive oil, melted
1 tablespoon whole-grain mustard
2 ounces Gruyère cheese, grated
2 slices roast beef

Steps:

Heat olive oil in a medium skillet over medium heat. Add onion, season with 1/4 teaspoon each salt and pepper, and cook, covered, stirring occasionally, about 5 - 7 minutes. Reduce the heat to medium-low, stir in thyme leaves and cook, uncovered, stirring occasionally, until the onions are golden brown, (add 1 tablespoon water to the skillet if the onions start sticking). Brush one side of each slice of bread with butter or oil. Form sandwiches with the bread, whole-grain mustard, Gruyère cheese, roast beef, and the onion mixture. Cook the sandwiches, covered, until the bread is golden brown and crisp and the cheese has melted, 4 to 5 minutes per side.