French Onion Grilled Cheese Sandwich

Indulge in the ultimate comfort food with a French Onion Grilled Cheese Sandwich! This delightful dish features gooey melted cheese and sweet, caramelized onions, all piled between crispy bread. Discover the best cheese options, perfect onion-caramelizing techniques, and creative variations to personalize your sandwich. Ready to elevate your lunch game?

Print Recipe Pin Recipe

Ingredients

2 large onions, thinly sliced

4 tablespoons unsalted butter

1 teaspoon sugar

Salt, to taste

1/4 teaspoon black pepper

1 tablespoon balsamic vinegar

6 slices of good quality bread (like sourdough or ciabatta)

6 slices of Gruyère cheese (or your preferred melting cheese)

6 slices of sharp cheddar cheese

1 tablespoon fresh thyme leaves (or 1 teaspoon dried thyme)

2 tablespoons olive oil for grilling

Instructions

In a large skillet, melt the butter over medium heat. Add the sliced onions and stir to coat.

Sprinkle the sugar, salt, and pepper over the onions. Cook the onions for about 20-25 minutes, stirring occasionally, until they are caramelized and golden brown.

Once the onions are caramelized, add the balsamic vinegar and fresh thyme, and cook for an additional 2-3 minutes. Remove from heat and set aside.

Heat a non-stick skillet or a panini press over medium heat. Spread olive oil on one side of each slice of bread.

Assemble the sandwiches by placing a slice of bread, then adding a layer of Gruyère cheese, a few spoonfuls of the caramelized onion mixture, a slice of cheddar cheese, and finally another slice of bread.

Place the sandwiches in the skillet or panini press, oiled side down. Cook until golden brown and crisp, about 4-5 minutes. Flip and repeat for the other side.

Once both sides are crispy and the cheese is melted, remove from heat and let them cool slightly before slicing.

Prep Time, Total Time, Servings: 15 mins | 45 mins | 3-4 servings

- Presentation Tips: Cut each sandwich in half diagonally and arrange on a serving platter. Serve with a small bowl of warm tomato soup for dipping, and sprinkle fresh thyme leaves on top for garnish. Enjoy!