French Onion Stuffing.

A holiday stuffing all your guests will love! Bakery croissants, winter thyme, caramelized onions, wild mushrooms, and Gruyère cheese come together to create the most delicious stuffing. It has all the familiar flavors of a rich, slowly simmered French onion soup, only baked into stuffing. It’s just as delicious served as a holiday side dish as it is enjoyed as a meal. Prep everything in advance, then bake just before dinner for easy holiday entertaining!

Stuffing has never really been a traditional side dish at our family Thanksgiving. I’m sure my aunt, who hosts Thanksgiving every year in Pennsylvania, serves stuffing. But since we moved to Colorado when I was a kid, it’s just never been part of our holiday table. Not at Thanksgiving or Christmas!

I guess stuffing was never a dish either of my parents particularly enjoyed, so we simply didn’t make it for our Thanksgivings in Colorado.

That’s since changed after I realized just how much everyone loves a classic stuffing. Early on, I tried more traditional recipes, but they were never really touched. Then one year, I decided to switch things up and created my first butternut squash stuffing. This one actually got eaten!

The following year, I made a croissant stuffing. This was the stuffing that changed the game for my family and so many of you guys. It’s become such a popular recipe!

This year, I wanted to create something new, with more of a French onion soup vibe. Think sweet caramelized onions simmered in wine, then tossed with big, buttery pieces of bakery croissants. It’s like a rich French onion soup baked into croissants with melty Gruyère cheese and fresh winter thyme.

All those classic, rich flavors that hit just the right notes this time of year. And it’s such a beautiful dish to serve on any holiday table!

Best of all, you can prep everything ahead of time and simply bake before dinner, saving yourself some work on Thanksgiving Day. It’s such a delicious dish to share with everyone this holiday season!

Here are the details

Ingredients

• croissants
• salted butter
• yellow onions
• celery
• mixed mushrooms
• white wine
• worcestershire sauce
• cayenne pepper
• garlic
• fresh thyme
• broth 
• eggs
• shredded Gruyère or Swiss cheese
• blue cheese (optional, but it might be the secret!)
• flaky sea salt 

The Steps

Step 1: Toast the croissants.

Start with day-old bakery croissants. Tear them into a mix of big and small pieces, arrange on a baking sheet, and dot with butter. Toast until lightly golden. This helps the croissants soak up all that delicious French onion flavor without getting soggy.

Step 2: Caramelize the onions.

Melt the butter in a large skillet, then add the sliced onions, salt, and pepper. Cook until deeply golden and caramelized. This takes a little time, but it’s what gives the stuffing that classic French onion soup flavor.

Add the white wine and 1 tablespoon of Worcestershire sauce. Let everything simmer for a few minutes. The Worcestershire adds a rich, savory depth that makes the onions even more delicious.

Step 3: Add the mushrooms and herbs.

Add the remaining butter, celery, wild mushrooms, garlic, and fresh thyme. Cook until the mushrooms soften, then pour in the broth. Simmer for a few minutes to bring all those flavors together.

Step 4: Assemble the stuffing.

Whisk the eggs with a little broth, crumbled blue cheese, and Gruyère.

You can leave out the blue cheese, no problem! But I will say, I think it’s the secret ingredient here, and everyone I’ve served this to agrees. The trick is to use an inexpensive, pre-crumbled blue cheese. It has a milder flavor and melts beautifully into the stuffing, adding just the right amount of sharpness and a subtle peppery bite without being overpowering.

Add the toasted croissants and gently toss. Fold in the caramelized onions, mushrooms, and all that buttery broth.

Transfer everything to a baking dish and finish with more Gruyère. You want plenty of cheese on top!

Step 5: Bake.

Cover and bake until the stuffing is set, then remove the foil and continue baking until the top is golden and the cheese is melted. Finish with fresh thyme and flaky sea salt.

Serve warm, right alongside your Thanksgiving turkey and all the other holiday sides!

Notes, Tips, and Tricks

The croissants: Use good bakery croissants, preferably a day or two old. I love having a mix of bigger and smaller pieces. The smaller pieces soak up the buttery broth, while the bigger pieces get golden and crisp on top.

The onions: Don’t rush them! The more golden and caramelized, the better the flavor. The wine and Worcestershire sauce add that extra richness you get from a really good bowl of French onion soup.

The cheese: Gruyère is my favorite here. It’s nutty, salty, and melts beautifully. Swiss cheese works too, but Gruyère gives you the best French onion flavor. And don’t skip the blue cheese if you can help it! It adds a subtle richness and just the right amount of bite.

The broth: Start with less and add more as needed. Croissants are buttery and delicate, so you don’t want to oversaturate them. The center should be soft and moist with a golden, slightly crisp top.

Make ahead: This is such a great Thanksgiving dish to prep ahead. You can caramelize the onions and cook the mushrooms up to 2 days in advance. Toast the croissants the day before, too. Store everything separately, then assemble the stuffing the night before and refrigerate. Bake just before dinner, adding a splash of broth if needed.

For holiday entertaining: If oven space is limited, bake the stuffing earlier in the day, then rewarm, covered, at 325°F until hot throughout. Remove the foil for the last few minutes to get that golden, crispy top back. So easy, and one less thing to worry about when everyone arrives!