Description
This French Onion Grilled Cheese is a deliciously indulgent sandwich featuring deeply caramelized onions, a blend of melted Gruyère and mozzarella cheeses, and crispy buttery sourdough bread. Perfect for a comforting lunch or dinner, this sandwich is enriched with the savory sweetness of onions and hints of thyme and balsamic vinegar, making it a gourmet twist on a classic grilled cheese.
Ingredients
Scale
Bread & Butter
- 4 slices sourdough or thick-cut bread
- 2 tablespoons butter (softened)
- 1 tablespoon olive oil
- 1 tablespoon mayonnaise (optional, for extra crispiness)
Caramelized Onions
- 1 large yellow onion (thinly sliced)
- 1/2 teaspoon salt
- 1/4 teaspoon black pepper
- 1/2 teaspoon fresh thyme leaves or a pinch of dried thyme
- 1 teaspoon balsamic vinegar (optional)
Cheeses
- 1/2 cup shredded Gruyère cheese
- 1/2 cup shredded mozzarella or Swiss cheese
Instructions
- Caramelize the onions: Heat olive oil in a skillet over medium heat. Add the thinly sliced onions along with salt, pepper, and thyme. Cook slowly, stirring often, for 20 to 25 minutes until the onions are deeply golden and caramelized. Stir in balsamic vinegar if using, then remove from heat.
- Prepare the bread: Butter one side of each slice of bread. Place two slices butter-side down on a cutting board. Optionally, instead of butter, you can spread a thin layer of mayonnaise on the outer sides of the sandwiches for an extra crispy golden crust.
- Assemble the sandwiches: On each buttered slice on the cutting board, evenly distribute the shredded Gruyère and mozzarella cheeses. Top the cheese with a generous spoonful of the caramelized onions. Cover with the remaining bread slices, butter-side up (or mayonnaise side up if using).
- Grill the sandwiches: Heat a clean skillet over medium heat. Place the sandwiches in the skillet and cook for 3 to 4 minutes on each side, pressing gently with a spatula, until the bread is golden brown and the cheeses have melted fully.
- Serve: Let the sandwiches rest for 1 minute to allow the cheese to set slightly. Slice each sandwich and serve warm, ideally paired with tomato soup or a light green salad.
Notes
- Add a splash of white wine or beef broth to the onions while cooking to deepen the flavor.
- Use mayonnaise on the bread exterior instead of butter for an extra golden and crispy crust.
- Pairs wonderfully with tomato soup or a fresh green salad to balance the richness.
- Prep Time: 10 minutes
- Cook Time: 25 minutes
- Category: Main Course, Sandwich
- Method: Stovetop
- Cuisine: French-Inspired
