French Onion Grilled Cheese Sandwich with melty Gruyere and caramelized onions make the best comfort food. It has all the flavors of a classic French onion soup, but quicker to make and portable! Your taste buds will swoon!
This grilled cheese with melty Gruyere and caramelized onions doesn’t disappoint at all. And if you add turkey slices leftovers, it feels like an unending Thanksgiving celebration!
Well, hello, Thanksgiving leftovers!
But first, let’s talk grilled cheese.
I rarely post anything cheese-y; however, I’m in love with this raspberry and chocolate grilled cheese combo and avocado toast with grilled cheese. If you haven’t tried these recipes, then you should!
What kind of cheese is best for grilled cheese
A great grilled cheese sandwich can be made out of lots of different cheeses, and my favorites are:
- Gruyère. It’s rich, complex, and melts well in the heat. Plus, it’s so creamy good!
- Swiss. I like the unique nutty flavor when it melts; however, be sure to use a good-quality cheese
- Cheddar. Not my first pick as it tends to get too oily but I like the way mild cheddar melts
Ingredients
- Gruyere cheese. This is the most important ingredient that you can’t miss
- Onion. Either one works; however, I like sweet onion
- Bread. Either sourdough toast or any toast, and I suggest thicker slice
- Beef stock or balsamic vinegar to moisten the onion and bring additional flavors. Another option is to use bourbon, marsala wine, or light beer
- Salt
- Thyme, whole-grain mustard. These are optional but they will add more flavors to the sanndwich
- Butter, olive oil
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How to make the best grilled cheese sandwich
- Cook the onions until it gets caramelized, then sprinkle with a generous pinch of salt and beef stock
- Spread the butter and whole grain mustard on one side of each piece of bread. Add turkey (optional), caramelized onions, grated Gruyere on the inside of the bread and top with second piece of bread that is spread with the butter and grain mustard
- Melt butter in a skillet over medium until beginning to foam. Add prepared sandwich and turn heat on to low. Make sure that you aren’t burning the butter and flip as soon as one side is golden brown and continue with other side. This process should take 8-10 min on each side
Kitchen tools
Making the best cheese sandwich doesn’t require fancy kitchen equipment. And most of the time will need a skillet or cast-iron skillet.
Kitchen note
Anyone can make grilled cheese, but not all grilled cheese is done equally. There are several keys and elements to make the best cheese sandwich.
- Shredded is best so the cheese will melt evenly
- Thick-sliced bread works better!
- Low heat. Yes, don’t rush the process or you will compromise the golden crust
Save some time and caramelize the onions ahead of time. Caramelized onions can be stored in an air-tight container for up to 1 week or in a freezer for up to 3 months.
Variations
It’s possible to take this classic comfort food to another level. Here are some ideas you can try.
- Make it a Mediterranean grilled cheese sandwich by adding feta, olives, basil, spinach, red onions and tomatoes
- My favorite is adding jalapenos and make it jalapenos grilled cheese sandwich
- Keep it simple but elegant with crispy prosciutto, melon slices, and arugula cheese sandwich
- Or keep it classic with sloppy joe cheese sandwich
This French onion grilled cheese sandwich never disappoints; however, you can always go with the classic and make a turkey grilled cheese sandwich with the homemade cranberry-orange sauce.
French Onion Grilled Cheese Sandwich
Ingredients
- 4 slices sourdough bread or cheese bread
- 1 small sweet onion thinly sliced
- 2 teaspoons whole-grain mustard
- Generous pinch of salt
- 1 teaspoon fresh thyme
- 4 tablespoons beef stock or balsamic vinegar
- 1 cup grated Gruyere cheese
- 2 tablespoons olive oil
- 2 tablespoons unsalted butter
Instructions
Caramelized onions
- Coat the bottom of the pan with olive oil and heat the pan on medium high heat until the oil is shimmering. Add the onion slices and stir to coat the onions with the oil. Spread the onions out evenly over the pan and let cook, stirring occasionally for 10 minutes. Sprinkle some salt and pour the stock. Continue stirring until onion caramelize into a beautiful deep golden brown. Set aside.
Grilled cheese sandwich
- Spread the butter and whole grain mustard on one side of each piece of bread. Add turkey, caramelized onions, grated Gruyere on the inside of the bread and top with second piece of bread that is spreaded with the butter and grain mustard
- Melt butter in a skillet over medium until beginning to foam. Add prepared sandwich and turn heat on to low. Make sure that you aren’t burning the butter and flip as soon as one side is golden brown and continue with other side. This process should take 8-10 min on each side
Sherry Ronning says
Yummm! What is not to love about this French Onion Grilled Cheese Sandwich!! I love this recipe!
Mandy Applegate says
French onions in a grilled cheese sandwich?? I’m in heaven!!
Lynn Polito says
Yum! This is so delicious!!
Jennifer says
Heck ya, I ate 2 of them! So good!
Sarah says
Holy moly! This was next level grilled cheese! This was my first time using Gruyere and it is going to be a regular for me now!
Erin says
What a genius idea! I made them immediately after finding the recipe and loved them! So tasty – thanks!
Alex says
My wife made these for dinner and wow! They were really great! I’ll make them again next week. 🙂
Kim says
Holy yum! So, so delicious, these are going to be on the regular rotation!
Healing Tomato says
I made this yesterday and boy, was it delicious!!! I am a huge fan now of these French Onion grilled cheese. Never thought I would like it because it’s just a very unique recipe. Ate t with butternut squash soup.
Mikayla says
Just Wow! This ‘sandwich’ tasted like a decadent full on meal, I didn’t even need a bowl of soup to go with it.
Brianna says
Two classics in one great sandwich!! These caramelized onions are positively divne.
Debbie says
YUMMMMM!! What a ingenious twist on on classic. We love french onion soup at my house and making it into a grilled cheese with all of those flavors was a HUGE hit. This recipe is a keeper for sure,
Chandice Probst says
Now this is the only way I want to make grilled cheese! Thanks a lot… But seriously thank you! ☺️So much flavor than a traditional grilled cheese and so way to make!
Amy Casey says
I love this idea for a grilled cheese sandwich. Along with a bowl of soup, it will be amazing!
Heidy says
This was a great recipe that our entire family enjoyed. I will definitely be making this again soon. Happy Holidays!
Looking forward to seeing your following recipe soon!!
Heidy