Description
This French Onion Grilled Cheese recipe combines sweet, caramelized onions with melty Gruyère and mozzarella cheeses, creating a rich and savory gourmet sandwich. Toasted sourdough or French bread is grilled to golden perfection with butter or olive oil, making it a comforting and flavorful main course perfect for lunch or dinner.
Ingredients
Scale
Caramelized Onions
- 2 tablespoons unsalted butter
- 1 large yellow onion, thinly sliced
- 1/2 teaspoon sugar
- 1/4 teaspoon salt
- 1 teaspoon fresh thyme leaves (or 1/4 teaspoon dried thyme)
- 1 teaspoon Worcestershire sauce
Sandwich
- 4 slices sourdough or French bread
- 1 tablespoon mayonnaise (optional, for bread)
- 1 cup shredded Gruyère cheese (or Swiss cheese)
- 1/2 cup shredded mozzarella cheese
- 1 tablespoon olive oil or additional butter for grilling
Instructions
- Caramelize Onions: In a skillet over medium heat, melt the butter and add the thinly sliced onions. Stir in the sugar and salt. Cook slowly, stirring often, until the onions turn deeply golden and caramelized, about 20 to 25 minutes. Add the thyme and Worcestershire sauce, stirring to combine, then remove from heat.
- Prepare Bread: If using mayonnaise, spread it on the outside of each slice of bread. This step helps create a crispy, golden crust when grilling.
- Assemble Sandwich: On the non-mayo side of two bread slices, layer half of the Gruyère and mozzarella cheeses, add a generous spoonful of the caramelized onions, then top with the remaining cheese. Place the second slice of bread on top, mayo side out.
- Grill Sandwich: Heat olive oil or butter in a clean skillet over medium heat. Place the sandwiches in the skillet and grill for 3 to 4 minutes per side, pressing gently with a spatula, until the bread is golden brown and the cheese has fully melted.
- Serve: Remove the sandwiches from the skillet, slice them in half if desired, and serve immediately for the best taste and texture.
Notes
- Make the caramelized onions ahead of time and store them in the refrigerator for up to 3 days.
- For a deeper flavor, add a splash of balsamic vinegar or white wine during the last few minutes of caramelizing the onions.
- Mayonnaise on the bread is optional but adds a great golden crisp texture.
- Use good quality sourdough or French bread for best results.
