Highlight
This French onion grilled cheese sandwich takes all the cozy flavors from French onion soup and tucks them into gooey, crunchy grilled cheese. Sweet onions cook down with nutty cheese that melts through crisp sourdough. Once you take a bite, you’ll want it again for lunch or dinner—trust me.
After I tried French onion soup at a little bistro, I dreamed about those rich flavors every single day. The first time I made this sandwich, it vanished almost instantly. Now it’s the comfort I crave most.
Tasty Ingredients
- Sharp white cheddar: Gives the sandwich a little kick and melts nicely. Shred it yourself for best results.
- Gruyère cheese: Famous for that nutty meltiness, just like in French onion soup. Skip the bags—get a block for best gooey-ness.
- Hearty sourdough bread: Firm, tangy bread that stands up to all the toppings. The crustier the better.
- Beef broth or dry sherry: Loads of savory flavor. You can splash in water if you need, but broth or sherry adds more punch.
- Fresh thyme: Adds both freshness and that earthy smell. Fresh leaves do wonders here.
- Salt and black pepper: Gives the onions some balance and zip. Use cracked pepper if you've got it.
- Sugar: Helps the onions get super caramelized. Granulated white or cane both work.
- Yellow onions: Pick onions that are shiny and firm. Slice as evenly as you can for easy cooking.
- Olive oil: Mixed with the butter so the onions turn golden. Extra virgin tastes best.
- Unsalted butter: Makes everything creamy and toasts the bread. Go for European style if you want that rich flavor.
Quick How-To Guide
- Build the Sandwiches:
- On a cutting board, lay out all the bread pieces. Add a pile of caramelized onions onto two of them, then top with the melty cheese halves on top. Press them together, wait one minute for everything to settle, then slice and serve while gooey.
- Time to Melt the Cheese:
- Sprinkle cheddar and Gruyère evenly over each side of your bread in the skillet. Cover everything so the cheese melts evenly, and let it go until the bottoms are crisp and the cheese is seriously melty. Should only take a few minutes.
- Toast Your Bread:
- Pop the rest of the butter and oil into your pan on medium-low. Add all the bread slices and toast for a couple of minutes till they're golden on the bottom. Flip and do the other side.
- Deglaze & Add Thyme:
- Pour in broth, sherry, or water to loosen up the pan bits. Scrape up all the little caramelized pieces with a wooden spoon. Add thyme, stir for a minute, and then slide the onions into a bowl. Wipe out your pan for a fresh start.
- Get Them Brown and Tasty:
- With the lid off, toss in sugar, salt, and pepper. Stir it up, put the cover back, and let them go five minutes at a time. Stir each time. You want deep golden brown onions—should take about twenty minutes.
- Start the Onions:
- Heat up a big skillet with butter and olive oil on medium. Toss in your sliced onions and stir to coat them all. Cover and cook for five minutes till softening—this is where the sweet, roasted flavor starts.
Highlight
I can’t get enough Gruyère—the nutty flavor is a total nostalgia trip for me. Reminds me of eating in outdoor Paris cafés with family. This sandwich pops up every birthday or whenever we want something extra special on chilly nights.
How to Store
Wrap leftovers up good and stash in the fridge for two days tops. To warm up, use a skillet on low so the bread stays crisp and cheese stays gooey. Try to skip the microwave if you can, so the texture doesn’t get sad.
Ingredient Swaps
Out of Gruyère? Try Swiss or Emmental for something similar. If you don’t have sharp cheddar, go for regular cheddar or fontina. Want even more sweetness? Use Vidalia onions instead.
Ways to Serve
Pair it with tomato soup or a green salad if you want that café feel. A sharp pickle cuts through the cheese richness. Sprinkle some thyme on top to look fancy and add flavor.
How It Came About
This sandwich is a mashup of classic French onion soup—think caramelized onions and loads of Gruyère—with an all-American grilled cheese. You’re basically biting into the best of France and the US all at once.
Recipe FAQs
- → Which onions bring out the best taste here?
Go for yellow onions. Once they're cooked down, they're sweet but not overpowering, which works really well here.
- → What's the reason to mix Gruyère and cheddar?
Gruyère melts beautifully and adds a cozy nutty note. Sharp white cheddar brings in a bit of zip. Together, they taste even better.
- → How much time should I spend caramelizing the onions?
You’ll need to hang out by your stove for about 20 minutes, stirring now and then on a steady, low-ish heat to get them just right.
- → How do I keep the bread super crispy?
Pick a sturdy sourdough, keep your pan at a medium-low temp, and use both butter and oil so the bread browns evenly but doesn’t burn.
- → Can I swap bread or cheese for something else?
Absolutely! Use any hearty bread you like and switch up the cheese with Swiss or mozzarella, though the flavor will shift a bit.
- → What’s the best way to serve this sandwich?
Take it out of the pan, give it a minute or two to rest, cut it in half, and dive in while the cheese is still oozing and warm.