We’re cooking, eating, and posting a grilled cheese sandwich every day for 30 days. This is No. 19. See all of our grilled cheese sandwiches >> here << .
We’re always late to the flavor game…
We thought we were geniuses (genii?) when we thought to throw wine-braised onions on a grilled cheese sandwich with gruyere and call it the French Onion Grilled Cheese, for what else is a crock pot of French Onion Soup with a cheesy “crouton” than an open-faced grilled cheese sandwich floating on onion soup?

It’s been done before, so we’re not that inventive (not that we are trying to be in the first place), but we made it anyway because we knew it would be delicious.
And it was.
When caramelizing and braising the onions, ho ahead and just make 4 or 5 pounds of them. They take a good 40 minutes to cook down, so you may as well make a bigger batch, pull out enough for the sandwiches, and continue cooking the rest into actual French Onion Soup for the next day. You will already have the bread and cheese for the garnish, too.

French Onion Soup Grilled Cheese
makes 1 sandwich
Ingredients
1 tablespoon each grapeseed (or olive) oil and butter, for frying
2 slices of french baguette or french bread
1 tablespoon softened butter
enough shredded gruyere cheese to generously cover both slices of bread
about ½ cup wine-braised onions (see recipe below)
fresh thyme leaves
salt and pepper to taste
Directions
Heat grapeseed oil in frying pan over medium low heat. Add butter and allow to melt.
Spread each slice of French bread with softened butter. Add half the shredded cheese to one, pile braised onions on top, sprinkled with fresh thyme leaves, salt and pepper, then add the rest of the cheese. “Close” the sandwich with the other slice of bread, and gently press together.
Place the sandwich in the hot pan and cook until bread is toasted brown and cheese has started to melt. Carefully flip the sandwich over in the pan and cook until the other side is toasted brown and cheese has completely melted.
Remove the grilled sandwich from the pan and serve.
Wine-braised Onions
about 1 small clove garlic per 2 onions
onions (cook about 3-5 at a time, as you will find many uses for leftover caramelized onions)
olive oil
butter
bay leaf
fresh thyme
salt and fresh cracked pepper
red or white wine
beef stock (optional)
Directions
Cut the onions in half lengthwise, then slice thinly again lengthwise.
For every 1 large onion, heat about 1 teaspoon olive oil in a large, heavy-bottom pan over medium heat. Add the same amount of butter, allow to melt, then add minced garlic. Allow the garlic to soften (but not color), then add the onions. Stir to coat the garlic and onions in oil+butter, add a bay leaf and a small sprig of thyme, then turn down the heat to medium low (so onions don’t burn). Continue to cook the onions until they are soft and deep golden brown, 30-40 minutes (depending on how many onions you cook).
Add about ¼ cup red or white wine (doesn’t matter), and allow to cook down with the onions, another 5-7 minutes. You can also add beef stock, but I didn’t.
Remove from heat and set aside enough onions for grilled cheese sandwich. The rest, throw into a pot and make French Onion Soup.



{ 24 comments… read them below or add one }
I LOVE French Onion Soup and Grilled Cheese, so I’ll have to try this out sometime. I think it’s a pretty genius idea, even if it has been done before. ;)
All these grilled cheeses are looking AMAZING! Thanks for linking back to our French Onion Soup Grilled Cheese!
I’ve seen a lot of grilled cheese sandwiches this month but I think this is the best one! It’s hard to beat a good French Onion Soup, and now it’s going to be very hard to beat a French Onion Soup Grilled Cheese!!!! WOW!
This looks amazing! And you didn’t take any shortcuts to compromise in the flavor. I often make French Onion Soup from the Balthesar recipe, this is just brilliant! Why didn’t I think of this???? Thanks, it’s going into my recipe book.
This is amazing! You took two things that I usually like to have for lunch and combined it perfectly. Thanks for sharing!
Freakin genius :D!!!!
Wow. My mouth is watering just thinking about it!
My word, that looks ridiculously good!!
Holy gooeyness Batman! I couldn’t decide if I wanted to make the fried chicken waffle grilled cheese or the french onion soup grilled cheese this weekend so….I’m making both. You would have to combine my favorite things into buttery goodness. It’s all your fault if my friends find me in a food coma. I’ll be in the kitchen if you need me.
I wish I had not seen this. Now I have to drop everything, put on presentable pants and brush my hair, go to the market and buy onions and spend the rest of the afternoon ignoring my writing assignment and my dog and making this gorgeous thing which my onion-phobic husband won’t eat. I can’t wait!
This is genius! I love grilled cheese sandwiches but with onions… wow!
I am totally in AWE! I love french onion soup, anything with onions for that matter, and this sandwich looks like a total comfort food to me!! Great recipe!
oh my–my mouth is watering this sounds amazing. Why haven’t I thought of this before!?!?!?
Oh, this sounds like the perfect winter lunch! Can’t wait to try it…
I made these for this evening’s dinner and they were really good! I wish I had used red wine, and more of it. I did add the beef broth.
I don’t know about where everyone else lives, but in this l’il town, Gruyere was $15.98 a pound. There were 4 of us, so I got half a pound . . . and it was far more than I needed.
Wonderful recipe!
I have made this several times. I sometimes use Mozzarella cheese, and if you dont have cooking wines on hand add a TSP of Apple cider vinegar to the onions. Delish.
How about dunking this into the onion soup as you eat each bite! Yum!!!!!!
My husband loves french onion soup although it is not my first pick. But I do love grilled cheese, so I thought “How can I go wrong?” Well, with this recipe, you CAN’T! I made homemade tomato soup to go along with this and it was a wonderfully flavorful meal. This is truly one of the best grilled cheese sandwhiches I have ever eaten. Far and above any gourmet gcs you can buy at the fanciest resturaunts. I can’t wait to surprise company with this one. Thanks for sharing this recipe!
This really sounds good and I love grilled cheese sandwiches ,so I will have to make this!
OMG! How do I print this?
Copy and paste in a word document.
I am not much of a wine expert, what are some suggestions???
We add sauerkraut, a little whole grain mustard, and have a vegetarian ruben.
We had this sandwich for dinner tonight. We loved them. I’m sure thankful that I found your recipe. The taste of it all is so good! I’m thinkng of making them when the kids come up to visit…