French Onion Baked Chicken Breasts

These French Onion Baked Chicken Breasts will blow your mind with all the flavors of the incredible soup, but less hassle! Impress the whole family with super juicy, golden-brown chicken smothered in caramelized onion sauce!

What are the ingredients in the French Onion Baked Chicken Breasts?

Since we’re basically making a French onion sauce situation for the chicken to sit in while it bakes, you’ll need nearly all the same things you’d expect for a French onion soup: onions, liquids, thyme, etc., plus the chicken. Here’s a complete list of all the ingredients you’ll need and a little info for each:

• boneless skinless chicken breasts – This cut of chicken is really easy to find in my area and works really well for this recipe. However, I’ve included instructions for bone-in breasts and bone-in thighs as well.
• kosher salt & fresh ground black pepper – Use this to season the chicken, as well as for the onions and sauce later in the recipe! I strongly prefer fresh ground black pepper over pre-ground store-bought. Just trust me!
• olive oil & butter – Olive oil helps give a nice sear when browning the chicken, and using butter to cook the onions provides the best flavor. Together, they give a good balance of higher smoke point but delicious flavor.
• yellow onions – Two large onions are plenty for this recipe. It will actually look like a lot of onions at first, but they will cook down as they caramelize!
• fresh thyme – Fresh thyme is a signature part of French onion soup, so don’t skip. You just need the one fresh herb for this recipe.
• garlic – Another requirement for French onion soup. I strongly recommend using fresh garlic (over jarred) for the best flavor.
• all-purpose flour – A small amount of flour is what thickens up the sauce and gives a creamy finish.
• white wine – Don’t worry, the alcohol cooks off and you can’t actually taste any wine. It actually helps open up the other flavors in the dish and brighten everything up!
• chicken broth – Use a good chicken broth to provide even more flavor overall.
• Worcestershire sauce – For that savory bite of flavor, I like to add a heavy dash of W sauce!
• Gruyère and/or Swiss cheese – The cheese is optional here, and that’s only because the chicken is so incredible and saucy and savory, you don’t NEED the cheese. But if you like it cheesy, I say go for it!

Equipment you’ll need to make this recipe:

The most important piece of equipment you’ll need for this recipe is a large, oven-safe skillet or pan. I love using the GreenPan nonstick brand for a lot of my cooking. Perfect browning results, easy to clean, and they just look good. For this recipe, I would use a GreenPan 12 inch Skillet. Of course any other 12 inch, oven-safe skillet would work too!

For utensils, I would recommend OXO 9-Inch Silicone Head Tongs (affiliate link!). The silicone tipped tongs eliminates scratches on your nonstick surface. Another option for nonstick surfaces is wooden tongs. I like this 3-Piece OXO Wooden Spoon Set (affiliate link!).

How to make this French Onion Baked Chicken Breasts recipe:

This is just an overview – please scroll down to the recipe card for ingredients and instructions! Despite looking super fancy, this meal is actually very simple to make, with the main thing to be aware of is how long it takes to cook.

To really caramelize the onions, you’re going to need to cook them for at least 20 minutes. Combined with the baking time for the chicken, it can make this recipe feel a little longer than others, but worth every single minute!

After all ingredient prep is done (cutting the onions, measuring out liquids, etc), begin the recipe by seasoning the chicken. I like to set the chicken on a cutting board or plate, pat dry with a paper towel, then use tongs to flip the chicken as I season. You can see this pictured here above!

Heat up the oil in a large nonstick and oven-safe skillet. Once it’s hot and shimmering, add the chicken breasts and brown them on both sides. This should take about 4-5 minutes on each side. Once both sides are seared and golden, remove them from the pan and set aside on a plate for now. They’ll finish cooking in the oven later.

Reduce the heat to medium and add the chunk of butter to the same pan used to sear the chicken. Once it has melted completely and started to froth, add the onions and thyme sprigs (yes, full sprigs, not cut up!) along with a very generous pinch of salt.

Cook, stirring frequently, for at least 20 minutes until the onions are soft and slightly golden (you could go even longer if you want!). They’ll cook down as well. Remove the sprigs of thyme from the pan when the onions are done. Now’s a good time to preheat the oven to 350F.

While the oven preheats, it’s time to make the sauce. Add the garlic to the onions and stir, cooking for another minute or so until you can smell the garlic well. Next, stir in the flour and cook for an additional minute or two to cook the ‘raw flour’ taste out of the sauce. The onions will start to thicken up a bit and stick together, which is normal.

Stir in the wine and cook for 2-3 minutes until you can no longer smell any alcohol. The onions will start to look a bit jammy. Finally, stir in the broth and Worcestershire sauce until you have a well mixed and slightly thickened onion sauce. 

At this point, turn off the burner. Nestle the seared chicken in the onion sauce and transfer the pan to the oven. Bake for about 15-20 minutes (depending on the size of your chicken breasts) until the chicken is cooked through and reaches an internal temperature of 165F. Add the shredded cheese during the last 5 minutes of baking, if you’re using it.

Once you remove the chicken from the oven, let it cool in the sauce for at least 5 minutes before digging in. My favorite way to serve this is to slice the chicken on a cutting board, put it on the plate with the sides, and then smother it in the onion sauce! Incredible 🙂

Below in the photos, I served this with roasted veggies and plain couscous. The onion sauce provides such an incredible flavor, it’s okay to keep the rest of the meal a bit more basic. There’s plenty of sauce for each serving!

Best tips for making French Onion Baked Chicken Breasts:

Here are my best tips for making this dish at home in your own kitchen:

• When selecting boneless skinless chicken for this recipe, look for chicken breasts that are about the same size. This helps them cook at the same rate and finish cooking at the same time.
• Don’t skip the wine, as it adds a valuable flavor enhancement to the recipe, and helps keep it closer to the original French onion soup style. I get the little $4 tiny box of sauvignon blanc for cooking!
• Be patient with the onions. Time and low heat are crucial for caramelizing the natural sugars in onions. You can’t speed this up with higher heat or anything else. You have to give it the full time!

What to serve with French Onion Baked Chicken Breasts?

Here in the photos below, I served this dish with oven roasted zucchini and bell peppers, plus some plain stovetop couscous. Here are some more ideas:

• over mashed potatoes or a baked potato
• with rice and roasted Fall vegetables
• smothered over sourdough toast
• served over egg noodles (or any pasta)

Ways to meal prep this recipe:

There are a couple ways to save time by preparing all or part of this recipe ahead. Here are some options:

1. Ingredient prep: It is possible to caramelize onions up to 4 days ahead and store them in the fridge, which could save you 20 minutes of cook time for this recipe. In this case, you would simply reheat the onions during Step 2 of the recipe and follow the rest as written.
2. Full recipe prep: You could prepare this entire recipe ahead of time (on the weekend, for example), then package it up for reheating during the week. Since the chicken has a sauce, it will reheat nicely and won’t dry out. It would reheat well in the microwave, in the oven, or in a HotLogic (see my HotLogic review here).
3. Prep & freeze: This main dish can be frozen for up to 3 months for best quality. I would recommend adding an additional cup of broth to the sauce so all the chicken can be covered as it freezes.

How to store French Onion Baked Chicken Breasts:

Store leftovers in an airtight container in the fridge for up to 4 days.

How to freeze French Onion Baked Chicken Breasts:

These cooked chicken breasts in onions sauce can be frozen for up to 3 months for best quality. I would recommend adding an additional cup of broth to the sauce so all the chicken can be covered as it freezes.

How to reheat French Onion Baked Chicken Breasts:

Reheat leftovers in any of the following methods:

• Microwave on High for 30 second blasts, stirring in between. If serving with a side of rice or other grain, add 1-2 TB of water to create steam while reheating.
• Oven: Make sure you’re using an oven safe container. Cover leftovers with foil and place in the oven. Turn oven on to 350F. Check leftovers at the 25 minute mark. Read my guide on How to Reheat Food Without A Microwave for more info.
• HotLogic is a mini personal countertop oven that reheats foods in about 90 minutes (see my HotLogic review here). I think this recipe would reheat well in an HL.

Recipe developed by Rachel Phipps.