It's spring, so I am looking for fresher, lighter dinners — but it's rainy, so I'm not entirely done with my oven just yet. Here's a warm, incredibly tasty dinner dish that suits spring perfectly. Take a mess of caramelized onions, soupy and rich, and add a touch of mustard and some chicken thighs. Braise in the oven, then broil with a handful of Gruyère cheese. It's rich without being heavy, and deeply flavorful without too much work. I'm having this for dinner tonight — care to join me?
But first, before I go any further, I should give credit where credit is due. I've mentioned in the past that I often get recipe inspiration from restaurant menus, and that's what happened here. I noticed a French onion chicken on the menu at Sweetwater Grill, in Steamboat Springs, Colorado, and I was instantly inspired. I didn't ask for the recipe, though, and in fact I didn't even order the dish. But the idea lodged in the back of my mind, and I returned to it this week.
There are four basic steps in this recipe: Caramelize the onions, then deglaze the pan with a bit of broth. Next, brown the chicken thighs and deglaze that pan as well, with a little more broth. Combine the onions and the chicken, with their respective sauces, and bake in a slow oven for half an hour. Then take off the lid, and broil with Gruyère. Eat with some good bread and a salad!
The chicken turns out succulent and tender, and it's nestled into a bed of rich, aromatic onions, spiked with tangy mustard. There is more than enough sauce to smother the chicken, and you could even eat it separately as a very rich soup.
This is such an easy dish. It takes some time to put together, though — primarily because of caramelizing the onions. Caramelizing onions, however, is a great do-ahead step. You could caramelize the onions on a Sunday night, or even prep the entire dish — then bake after you get home from work.
It pretty much goes without saying that this dish makes fantastic lunch leftovers, too. It would also freeze magnificently.
One last note: this recipe is a good example of how dirtying three pans (and consequently, needing to do more dishes later) can save you time. If you have more time to kill while making this recipe, you can condense everything into one big Dutch oven. But it will take longer; you would brown the chicken first, take it out, then make the sauce and pour it off, then caramelize the onions and their sauce — and finally layer everything back into the Dutch oven. If you don't want to wash three pans, then try this method! Using three pans just makes the process quicker.
3 tablespoons unsalted butter
2 pounds onions, sliced into thin half-moons
Kosher salt and freshly ground black pepper
4 garlic cloves, sliced
2 small sprigs thyme, leaves only
4-inch sprig rosemary
2 cups chicken broth, divided
1 tablespoon balsamic vinegar
2 tablespoons Dijon mustard
3 pounds boneless skinless chicken thighs
2 ounces Gruyère cheese, finely grated or shaved (about 1 cup)
Melt the butter in a deep 10-inch sauté pan over medium heat. When the butter has melted completely and foams up, add the onions. They will fill the pan to the top, at this point. Stir as you add the onions to coat them in the butter. Sprinkle lightly with salt and black pepper. Cook the onions for about 40 minutes over low or medium heat, stirring occasionally.
When the onions have developed an evenly light beige color throughout, add the garlic, thyme leaves, and whole rosemary sprig, and cook for a few minutes more, stirring frequently. Turn the heat up to high and cook for a further 5 minutes, stirring frequently. You want dark, slightly burnt spots to appear on the onions, and for them to develop a rich mahogany color. When the onions get quite dark, add 1 cup of the beef or chicken broth. Add it slowly, stirring and scraping the pan vigorously to scrape up any burnt or stuck-on bits. When the liquid has been added, bring it back up to a simmer and simmer lightly for 5 minutes, or until it is somewhat reduced.
Take the onions off the heat and pour them into a 3-quart oven-safe dish with a lid. (If you don't have a Dutch oven or another oven-safe dish with a lid, you can use a 9x13-inch baking dish. Just cover it tightly with a double layer of foil.)
Heat the oven to 325°F.
While the onions are cooking, brown the chicken. Heat another 10-inch or cast iron skillet over medium-high heat. Pat the chicken thighs dry and season lightly with kosher salt and black pepper. When the skillet is hot, add the thighs and brown for about 3 minutes on each side, 6 minutes total. When they've developed a golden-brown crust, remove from the pan and set on top of the caramelized onions in the baking dish.
Add the remaining 1 cup broth to the pan. Stir vigorously, scraping up any browned bits on the bottom of the pan. Whisk in the balsamic vinegar and Dijon mustard. Simmer for about 5 minutes or until reduced by half. Pour this sauce over the chicken and onions, and put the lid on the baking dish. The chicken and onions will look quite saucy; there will be plenty of liquid in the baking dish.
(At this point you can refrigerate the dish for up to 48 hours. Let it sit at room temperature for at least 15 minutes before baking, or else add about 5 minutes to the bake time.)
Bake at 325°F for 30 minutes. Remove the chicken from the oven and turn the heat up to broil. Take the lid off the baking dish, and sprinkle the cheese evenly over the top of the chicken. When the broiler has heated up, return the dish to the oven and broil for 3 to 4 minutes, or until the cheese is melted and golden on top.

Serve promptly in shallow bowls, with plenty of good bread to sop up the sauce, and a green salad on the side.
More Chicken Recipes from The Kitchn
Pictured above, left to right:
• Country Captain Chicken
• Lemon Garlic Chicken
• Hainanese Chicken With Rice from Mark Bittman
More (not pictured above)
• How To Roast a Chicken
• Roasted Chicken Thighs with Fennel & Lemon
• Chicken (or Tofu!) & Wild Rice Salad
(Images: Faith Durand)








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Comments (39)
Yum! Thanks for sharing this!
Looks amazing. One question: should the rosemary be minced or put in whole and removed later?
@sgaspar - thanks! The rosemary should be left whole; I'll clarify that in the recipe.
I am all about boneless skinless chicken thighs. Thanks for the recipe.
Looks great!
Question - where is that blue dish from? It's gorgeous.
This just got a collective "ohhhhhh" from my officemates!
@SarahBerneche it's a vintage mid-century dish from Holland. I think the maker is Royal Sphinx, Maastricht. They pop up pretty frequently on eBay and Etsy.
Question: Could I use leftover French onion soup?
It's still cool here in the Northwest - I will be making this soon!
OMG...drooooooling!!!
Very nice. This looks and sounds delicious.
Seriously fantastic idea! Kudos both to the Colorado restaurant and to you, Faith! This is going on my weekend menu!
Made this last night with leftover rotisserie chicken that I needed to use. It was the perfect rainy night warm you up soup. Delicious!
I have been thinking of this dish since you first posted. This one is going to be made soon if it sticks around in my head this long! Have to have some friends over to help me taste test!
making this right now! one thing though... i have a gas oven and no way is my le creuset gonna fit under the broiler! can i just bump the heat up and leave it in the oven once i add the gruyere?
I'm going to make this and deglaze with some white wine in place of some of the broth!
Faith, I made this yesterday and it was even tastier than I imagined. We have leftovers to test tomorrow which I suspect will only get better. My only regret was not picking up on your visual cue and and getting some crusty bread - it would have been the thing to get the last of that sauce. Thank you for posting this wonderful recipe as this is a keeper.
This looks really yummy. I would use only two pans though, and I think it would be just as fast... one ovenproof pan to caramelize and deglaze the onions, and a second pan to sear the chicken. When the chicken has browned, remove it and put it on top of the onions while you make the sauce, then pour the sauce over the chicken and onions in the first ovenproof pan.
I love everything about this recipe! It was AMAZING! Thank you!
I just made this for dinner, and it was DELICIOUS. Good with roasted asparagus and a baguette on the side. Definitely bookmarking this and putting it into my regular rotation :)
I'm making this one for dinner tonight, except I halved the recipe; and added some pinot noir in addition to the balsamic vinegar. We'll see how it turns out!
I have many chicken breasts...can I use them for this great sounding recipe?
Had to come back and comment ... I made this on Fri night and it was a hit with the whole family, from my 2yo son to my 63yo mom. A keeper for sure!
As a note to LizBWebb, I think the thighs would be preferable for the extra fat ... better for browning and a richer end product. I had thought about using breasts too, but I'm glad I opted for thighs. I'd love to her your results if you try it though!
I made this the other night and halved the recipe. It was very good, but was not falling-apart tender. I think a slightly longer braise (maybe an hour?) would make it absolutely perfect. Also, you can definitely consolidate and do everything in one or two pans. Take the onions out and brown the chicken in the same pan.
Made this last night and it was fabulous. It took a little bit of time but most of it was of the hands off variety as I waited for the onions to caramelize. I did use two pans only because I needed to maximize my time to get dinner on the table soon but this could've easily been done in one. I served it over mashed cauliflower and it was a great vehicle to sop up the yummy sauce. I'll be making this again so thank you!
I make something very much like this and we call it, "Stinky Chicken" due to the smell of the cheese when it heats. It is my 10 year old granddaughter's favorite meal and what she requests for her birthday. She has moved several states away recently so I sent her the recipe and she can make herself now. We do love mushrooms so we always use a lot of mushrooms to the pan as well.
I prefer boneless skinless chicken thighs browned in a skillet with a bit of pepper and garlic. I put them in the baking dish. Put diced onion and sliced mushrooms into the pan with a bit of olive oil or butter. Saute until tender, browning isn't necessary. Pour on top of the chicken. I deglaze the pan with white wine, my granddaughter adds a can of french onion soup concentrate to the pan of chicken. Cover the pan with foil and bake until the chicken is about 10 degrees from done, but thighs are forgiving so 30 minutes is fine. Pull the foil, add shredded cheese and put under broiler on low. Pull the dish when the cheese is melted with a bit of browning on the cheese. Let it sit for at least 10 minutes and serve with rice, a crisp salad and a green vegetable. Even a 10 year old can do it. :)
I made this recipe tonight for dinner and it was WONDERFUL! It will become a regular in my repertoire. It would be a great dinner for guests since the longest part of the preparation can be done ahead of time. I served the chicken with a butter leaf salad with tangelo supremes, dried cranberries & toasted walnuts, lightly dressed in a champagne vinaigrette and of course, crusty rustic French bread. Made an apple clafouti with apple brandy sauce and it was close to a perfect meal!
This is possibly one of my all-time favorite recipes.
Yup, still one of my favorites. It's SO GOOD.
I made this for a Mother's Day lunch for my mother and in-laws - between 6 of us and 4.5 pounds of chicken (16 thighs), we ended up with only 2 small thighs left over, so I would say it was a hit!
I think I will chop up the remaining pieces of chicken and thin out the onions and sauce with some extra broth, and serve it as chicken french onion soup for dinner tonight. Thanks for an AMAZING recipe!
This is remarkably delicious. As one of my friends said when I served it, "I haven't even eaten the chicken yet, I'm just enjoying the sauce!" Yummy rustic bread is crucial for soaking up all that deliciousness.
Thank you for this delightful recipe!!!
I love the idea of this recipe, but I am making it right now, and the proportions must be way off. 3 lbs of chicken for 4-6 people? I had my dad buy three pounds and there are probably 12 chicken thighs total-- I'm not even sure they will fit in my 5 quart dutch oven!! Also I work in a store with wine and cheese, so I can safely say that 2 ounces (1/8 lb) of cheese will not make a cup of grated cheese... more like 1/4 cup.
Regardless, I love the recipe.. I'm just a little confused
This is also what I did - it's in the oven now and smells unbelievable!
I think there might be a step missing?? After you put the onions into the 3 quart ovenproof dish it says to heat up the oven...but then it says "while the onions are cooking..." I am assuming the onions go into the oven then?
Also agree with the 2 oz of cheese not making a cup of grated...but who is measuring anyway when it comes to cheese? Just pile it on!
Just got done making this dish and it came out great!! Thanks!
This dish was amazing! I used chicken breasts and it turned out very juicy and tender. All three of my kids said that they can't wait for me to make it again.
I am definitely making this today... My hubby HATES mustard. It is the one thing he really can't stomach. Any thoughts on what to replace it with? Will omitting it change the dish dramatically?
I made it without mustard and it was amazing! Thanks for this awesome recipe! Definitely a new go-to.
I'm assuming you brown the chicken in a little oil?? Correct???