French Onion Grilled Cheese Sandwich

Indulge in the ultimate comfort food with this savory French onion grilled cheese sandwich recipe! Featuring sweet caramelized onions and a blend of gooey Gruyère and sharp cheddar, all nestled between crispy sourdough slices, this sandwich is a delightful treat for any occasion. Follow along for step-by-step instructions and tips to perfect this tasty creation. Click to explore the full recipe and start your grilling adventure today!

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Ingredients

2 large onions, thinly sliced

3 tablespoons unsalted butter

1 tablespoon olive oil

1 teaspoon sugar

Salt and pepper to taste

1 teaspoon dried thyme

4 slices sourdough bread

1 cup grated Gruyère cheese

1 cup grated sharp cheddar cheese

2 tablespoons Dijon mustard

Optional: Fresh parsley for garnish

Instructions

Caramelize the Onions: In a large skillet, melt the butter with the olive oil over medium heat. Add the sliced onions and sugar, seasoning them with a pinch of salt. Cook for about 15-20 minutes, stirring occasionally, until the onions are soft and caramelized to a golden brown color. If they start to brown too quickly, reduce the heat. Add the dried thyme towards the end of cooking and mix well. Remove from heat and set aside.

Prepare the Bread: Spread Dijon mustard on one side of each slice of sourdough bread. This will add an extra layer of flavor to the sandwich.

Assemble the Sandwich: On two slices of bread (mustard side up), layer half of the Gruyère cheese, then spoon half of the caramelized onions on top. Add the remaining cheese and then cover with the other slices of bread (mustard side down).

Grill the Sandwich: In the same skillet (or a clean one), melt a little butter over medium heat. Place the sandwiches in the skillet and cook for about 4-5 minutes on each side, pressing down slightly, until the bread is golden and crisp and the cheese is melted.

Slice and Serve: Once grilled to perfection, remove the sandwiches from the skillet and let them rest for a minute. Slice each sandwich in half and garnish with fresh parsley if desired.

Prep Time, Total Time, Servings: 10 mins | 35 mins | Serves 2

- Presentation Tips: Serve the sandwiches warm on a cutting board or a rustic plate. Pair them with a small bowl of homemade tomato soup on the side for a delightful dipping experience!