French Onion Grilled Cheese Sandwich - Best Recipe for Dinner

Just when you think sandwiches can’t level up anymore, along comes this French onion grilled cheese—aka the mashup nobody asked for but everybody needs. It’s rich, cheesy, and downright addictive. IMO, this belongs on the list of the Best Sandwich Recipes you’ll ever try.

Here’s the twist: most sandwiches tuck the cheese inside and call it a day. Not this one. Nope—I doubled down and added melty goodness both inside AND outside. Because honestly, when it comes to Grilled Cheese Recipes Gourmet, the motto is simple: more cheese, less problems.

The vibe? Think French onion soup…but portable. You’ve got those golden, caramelized onions, a hearty slice of bread (heck, try it with sourdough, brioche, even chapati if you’re feeling adventurous), and an ooey-gooey cheese layer that’s impossible to resist. No, it’s not “soup in a bowl,” but it nails the same comfort-food magic.

Here’s why you’ll be obsessed: gooey white cheddar or Swiss inside, then Gruyère (or even Fontina + Parmesan) melted right on top. Yep, this is Fancy Grilled Cheese taken to a whole new level. And the cooking method? Genius. You don’t flip these bad boys. Instead, you sear one side in a skillet, then slide the pan into the oven. A quick broil crisps up the bread, then you pile on that glorious cheese topping and broil again—just like with French onion soup.

The best part? You can tweak it however you want. The “perfect” butter-to-bread ratio really depends on the bread you’re rocking, so consider my measurements more of a guide.

So, ready to ditch basic toasties and dive into Gourmet Grilled Cheese territory? This Onion Grilled Cheese might just claim the crown for the Best Grilled Cheese you’ve ever sunk your teeth into.

French Onion Grilled Cheese Sandwich - Best Recipe for Dinner

Get ready for a sandwich experience like no other! Sweet, slow-cooked onions nestle inside melty white cheddar, while the top is crowned with a golden, bubbly layer of Gruyère. This Onion Grilled Cheese is indulgent, cozy, and will totally redefine your sandwich game.

• Prep Time: 10 minutes
• Cook Time: 1 hour
• Servings: 2
• Course: Lunch, Main Course
• Author: Aleda

Ingredients

Caramelized Onions:

• 2 large yellow onions (about 1 lb), peeled and thinly sliced
• 1 tbsp olive oil
• 1 tbsp unsalted butter
• ½ tsp sugar
• ¼ tsp salt
• 2 cloves garlic, minced
• 3 tbsp dry red wine (I like Malbec)
• A pinch of cinnamon
• Freshly ground black pepper

Grilled Cheese:

• 4 large slices of sourdough bread
• 4 tbsp unsalted butter, melted
• ⅛ tsp dried thyme
• ⅛ tsp dried rosemary
• 7 oz white cheddar, shredded or 4 slices
• 3 oz Gruyère, shredded

Instructions

1. Heat olive oil in a large skillet or cast-iron pan over medium heat. Add the sliced onions and cook, stirring frequently, until they soften, about 20 minutes.
2. Stir in butter and continue cooking for another 20 minutes, stirring every few minutes. Lower the heat if the onions start to brown too fast.
3. Sprinkle in salt, sugar, cinnamon, and black pepper, and cook for an additional 15 minutes until the onions take on a deep, golden color. Add garlic about 12 minutes into this stage.
4. Pour in the red wine and scrape up all the browned bits from the pan. Let it simmer 2–3 minutes until mostly evaporated. Remove from heat and set aside.
5. Mix melted butter with thyme and rosemary. Brush one side of each bread slice with the herbed butter.
6. Place two slices, butter-side-down, in the skillet. Layer on the caramelized onions, then add the white cheddar. Top with the remaining bread slices, butter-side-up.
7. Cook over medium heat for 5 minutes, or until the bottoms are golden and crisp. Meanwhile, preheat your oven to broil.
8. Transfer the skillet to the oven and broil 1–2 minutes until the tops turn golden. Remove, sprinkle Gruyère over the sandwiches, and broil again 1–2 minutes until bubbly and melty.
9. Slice in half, sprinkle with extra rosemary and thyme if desired, and serve immediately.

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