French Onion Grilled Cheese

A rich twist on the classic grilled cheese, this french onion Grilled cheese features deeply caramelized onions, melty Provolone and Gruyère cheeses, and crispy golden bread. It’s the perfect comfort meal for any time of day, delivering all the flavor of French onion soup in a satisfying handheld form.

Why You’ll Love This Recipe

• Packed with umami-rich, sweet caramelized onions.
• Features a perfect balance of Provolone and Gruyère cheeses.
• Crispy, golden bread with a creamy, cheesy center.
• Ideal for lunch, dinner, or a cozy snack.
• Customizable with different breads and cheeses.

Ingredients

(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)

• 2 tablespoons salted butter
• 1 tablespoon extra virgin olive oil (or additional butter)
• 2 large white onions, thinly sliced
• 2 large yellow onions, thinly sliced
• 2 tablespoons Worcestershire sauce
• 2 teaspoons spicy brown mustard
• 1 teaspoon Italian seasoning
• ½ teaspoon garlic powder
• 1 teaspoon granulated sugar (optional, for caramelization)
• ½ teaspoon fresh ground black pepper
• ½ teaspoon fine sea salt
• 6 slices bread (French, sourdough, brioche, etc.)
• 3 tablespoons mayonnaise (optional, for spreading)
• 6 slices Provolone cheese
• 6 slices Gruyère cheese

Directions

1. Caramelize the Onions: Heat butter and olive oil in a large skillet over medium heat. Add sliced onions, Worcestershire sauce, mustard, Italian seasoning, garlic powder, sugar (if using), salt, and pepper. Stir to combine.
2. Cook onions for 20–25 minutes, stirring occasionally, until caramelized and golden brown. Cook off any excess liquid. Set aside.
3. Assemble the Sandwiches: Heat a clean skillet over medium heat. Spread mayonnaise on one side of each bread slice if using.
4. Place one slice of bread in the skillet, mayo side down. Top with 1 slice of Provolone, a generous portion of caramelized onions, and 1 slice of Gruyère. Top with another slice of bread, mayo side up.
5. Cook for 2–3 minutes per side, or until golden and crispy, and the cheese is melted.
6. Repeat with remaining ingredients to make 3 sandwiches total.
7. Slice and serve hot with your favorite side.

Servings and timing

Prep Time: 15 minutes
Cooking Time: 30 minutes
Total Time: 45 minutes
Servings: 3 servings
Calories: 822 kcal per serving

Variations

• Cheese Swap: Use Swiss, mozzarella, or sharp white cheddar for different flavor profiles.
• Bread Options: Try rye, ciabatta, or multigrain for texture and flavor variety.
• Add Protein: Include slices of roast beef, or turkey for a hearty upgrade.
• Herb Butter: Spread garlic herb butter on the bread for added flavor.
• Vegan Version: Use plant-based cheese and butter with caramelized onions for a vegan twist.

storage/reheating

Store any leftover sandwiches in an airtight container in the fridge for up to 2 days. Reheat in a skillet or toaster oven for 5–7 minutes to regain crispiness. Avoid microwaving, as it can make the bread soggy. You can also prep the caramelized onions ahead and store them separately for up to 4 days.

FAQs

Can I make the caramelized onions in advance?

Yes, store them in the fridge for up to 4 days to save time.

What’s the best bread to use?

Thick-sliced sourdough, French bread, or brioche work best for crispiness and structure.

Can I use only one type of onion?

Yes, but using both white and yellow onions adds depth and complexity.

What other cheeses can I use?

Mozzarella, Swiss, white cheddar, or fontina are all great options.

Do I need mayonnaise for the bread?

No, but it helps the bread brown evenly and adds flavor. Butter works well too.

How do I get perfectly crispy bread?

Use medium heat and press the sandwich gently with a spatula while cooking.

Can I freeze these sandwiches?

Freezing is not recommended, but you can freeze caramelized onions for later use.

How do I avoid soggy bread?

Use thick bread slices, don’t overload the onions, and cook off all liquid.

Is this kid-friendly?

Yes, especially if you reduce the onion quantity or use milder cheese.

What can I serve with this grilled cheese?

Tomato soup, salad, chips, or roasted vegetables pair wonderfully.

Conclusion

French onion grilled cheese is a flavorful, comforting twist on a beloved classic. Rich with caramelized onions and melty cheeses, it’s an indulgent yet simple meal that hits all the right notes. Serve it up hot and gooey with your favorite sides and enjoy the cozy, satisfying experience.

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