French Onion & Roast Beef Grilled Cheese Sandwich

By á-34480

Grilled cheese sandwiches are just fine with cheese. But when the cheese is Gruyère, and you add roast beef and caramelized onions, it's over the top.

Ingredients

• 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

Preparation

Step 1

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.