Description

This French Onion Grilled Cheese sandwich is a delightful twist on the classic French onion soup, featuring sweet and savory onion jam, gooey Gruyere and white cheddar cheeses, and buttery toasted bread topped with a sprinkle of Parmesan for extra flavor. Perfect for a comforting lunch or dinner, this sandwich combines rich flavors with satisfying textures that will keep you coming back for more.

Ingredients

Onion Jam:

3 tablespoons Olive Oil
8 Small Onions, sliced
1 Rosemary Sprig
2 Bay Leaves
3 Thyme Sprigs
½ cup Brown Sugar
½ cup Red Wine
1 tablespoon Balsamic Vinegar
1 (10.5 ounce) can French Onion Soup

Grilled Cheese:

8 slices Thick Sliced Bread
½ cup Butter, softened
1 cup Gruyere Cheese, shredded
1 cup White Cheddar Cheese, shredded
Onion Jam (prepared from above)
3 tablespoons Grated Parmesan Cheese

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Instructions

Prepare Onion Jam: In a large skillet, heat the olive oil over medium heat. Add the sliced onions, rosemary sprig, bay leaves, and thyme sprigs. Cook, stirring occasionally, until the onions are caramelized and golden brown, about 25-30 minutes.
Add Sugar and Deglaze: Stir in the brown sugar until dissolved. Pour in the red wine and balsamic vinegar, cooking for an additional 2-3 minutes to deglaze the pan, scraping up any browned bits from the bottom.
Simmer and Thicken: Stir in the French onion soup, reduce heat to low, and simmer the mixture for 20-30 minutes until thickened and jammy. Remove the rosemary, bay leaves, and thyme sprigs. Set the jam aside.
Preheat Skillet: Preheat a skillet or griddle over medium heat to prepare for grilling the sandwiches.
Assemble Sandwich: Add 1 tablespoon of butter to the skillet. Place one slice of thick-sliced bread on the skillet. Layer with Gruyere cheese, a generous portion of onion jam, then cheddar cheese. Top with another slice of bread.
Grill First Side: Grill the sandwich for 3-4 minutes until the bread is golden brown and the cheese begins to melt. Add more butter to the pan before flipping.
Flip and Grill Other Side: Carefully flip the sandwich and grill for another 3-4 minutes until the second side is golden and the cheese is fully melted.
Finish and Serve: Remove the grilled cheese from the heat, sprinkle both sides with grated Parmesan cheese. Repeat the process with the remaining ingredients to make additional sandwiches. Slice each sandwich in half and serve hot.

Notes

For best results, use thick sliced sturdy bread like sourdough or country loaf to hold the filling well.
The onion jam can be stored in the refrigerator for up to one week and used for other recipes.
You can substitute red wine with white wine or vegetable broth if preferred.
To make the sandwiches crispier, cover the skillet while grilling to help melt the cheese thoroughly.
Make sure to remove all herb sprigs from the onion jam before assembling the sandwiches to avoid biting into tough stems.