This delicious Brussels Sprouts Au Gratin recipe is made with a delicious cheesy cream sauce, smoky bacon, and perfectly cooked brussels sprouts. If you are looking for a way to jazz up standard brussels sprouts, whether for a simple weeknight dinner or to add to your holiday menu, this decadent side dish is hard to beat!

Tasty Brussels Sprouts Au Gratin

I love brussels sprouts, ok?! After years of being boiled and steamed, it seems like collectively we have finally learned that roasting them in the way to go and if you’re anything like me, you can’t get enough. Roasting will always be one of my favorite ways to prepare brussels sprouts, but this delicious brussels sprouts au gratin is also something special.

The brussels sprouts are roasted until just tender and then covered in a creamy, flavorful, cheese sauce that is out of this world delicious. Topped with crispy bacon and shredded cheese, no one will want to turn these sprouts down.

recipe ingredients

Watch How to Make This Recipe

Au Gratin Ingredients

Note: full ingredients list & measurements provided in the Recipe Card, below.

  • Fresh brussels sprouts – trimmed and sliced in half before being roasted for a bit.
  • Bacon – brussels sprouts and bacon go together like a match made in heaven. The smoky bits of bacon in this dish are absolutely delicious.
  • Shallot – these have a milder flavor than onion that works really well in the cream sauce. 
  • Garlic – fresh is always best.
  • Arrowroot starch – if you have never used arrowroot starch before it is a great ingredient to keep in your pantry. It works as a thickener and a grain-free alternative to corn starch. 
  • Coconut milk – I always have full-fat canned coconut milk in my pantry and it works really well in this dish. You could also use regular whole milk if you prefer.
  • Chicken broth – this is used to make the cream sauce. You could use vegetable broth if you like.
  • Dijon mustard – adds a bit of tang and delicious flavor to the cream sauce.
  • Herbs and spices – dried thyme and nutmeg add an extra boost of flavor to the delicious sauce.
  • Shredded cheese – this recipe uses a combination of parmesan and shredded gruyere for a rich and flavorful dish. You could also use a sharp white cheddar cheese if you prefer.

Helpful Kitchen Tools

au gratin sauce

How to Make This Cheesy Brussels Sprouts Au Gratin Recipe

Note: full ingredients list & measurements provided in the Recipe Card, below.

While this cheesy brussels sprouts au gratin recipe is heavy on the flavor and decadence, it really could not be easier to make. Essentially, we’re just roasting the brussels sprouts, making the cream sauce, and then combining everything together in small casserole dish or skillet to finish baking. Trust me, it couldn’t get any easier!

Step One: The first step in making this dish is to prep and roast the brussels sprouts. To do this, just trim off the bottom of the sprouts and cut in half. Once all of the sprouts have been prepped, toss them in a little olive oil, season with salt and pepper, and roast at 400 degrees for around twenty minutes until they become tender.

roasted brussel sprouts

Step Two: While the brussels sprouts are roasting, it’s time to make the cream sauce! Start by cooking the bacon bits until crispy and then removing them from the pan. Next, you’ll add in the shallot and garlic and cook until tender and fragrant. Now it’s time to add the arrowroot starch to the garlic and shallot. The arrowroot starch will help to thicken the sauce and create a luscious creamy sauce to coat the brussels sprouts.

Step Three: Once the arrowroot has cooked for a minute, it’s time to add the coconut milk, dijon mustard, dried thyme, nutmeg, salt, and pepper. Let the sauce simmer for around eight to ten minutes before stirring in shredded parmesan cheese and half the bacon.

au gratin before going in the oven

Step Four: Once the cheese has melted, it’s time to combine the cream sauce with the brussels sprouts. Pour the sauce over the Roasted Brussels sprouts and give everything a stir until well combined. Next, sprinkle on the shredded gruyere cheese and remaining crispy bacon.

Step Five: Let the au gratin bake for around ten to fifteen minutes until the cheese has melted and the sides are bubbly. That’s it! I like to let the casserole cool for just a few minutes before serving but you still want everything to be nice and hot.

baked au gratin

Frequently Asked Questions

  • What can I use instead of arrowroot starch? Arrowroot starch is a grain-free alternative to corn starch. If you do not have arrowroot you can sub tapioca flour or even gluten free flour.
  • Does the coconut milk make this dish taste like coconut? No! There are so many other delicious strong flavors in this dish and using coconut milk will not make the au gratin taste like coconut. If you prefer, you could use whole milk or even half and half if you prefer.
  • Do I have to use bacon? Of course not, but I highly recommend it. If you do choose to skip the bacon, you will need to cook the shallot in garlic in a tablespoon of ghee or butter to replace the bacon fat.
  • Can I make this in advance? Yes! You can make this recipe a day in advance to make your holiday prep a bit easier. To make this dish in advance, prepare and bake the au gratin as written. Then, let it come to a complete cool before covering and placing in the fridge. When you are ready to reheat, remove the au gratin from the fridge and let it come to room temperature. Then, bake the casserole for 25-30 minutes, covered, until completely heated through.

Serving This Recipe for Thanksgiving Dinner?

Here are a few more delicious recipes to add to your menu:

Get all of our best Thanksgiving recipes, here!

au gratin in dish

I hope you give this Brussels Sprouts Au Gratin a try! It is creamy, cheesy, and so delicious  – the perfect addition to your holiday menu or weeknight dinner!

If you do give this recipe a try, I want to know! Leave a comment with a star rating below. You can also snap a photo & tag @allthehealthythings on Instagram. Your reviews help support All the Healthy Things and make it possible for me to continue to create the recipes you know and love.

brussel sprouts au gratin in dish

Brussels Sprouts Au Gratin

  • Author: Ashlea Carver
  • Prep Time: 10 minutes
  • Cook Time: 40 minutes
  • Total Time: 50 minutes
  • Yield: 6 1x
  • Category: Dinner
  • Method: Oven
  • Cuisine: American
  • Diet: Gluten Free
  • Author: Ashlea Carver
  • Prep Time: 10 minutes
  • Cook Time: 40 minutes
  • Total Time: 50 minutes
  • Yield: 6 1x
  • Category: Dinner
  • Method: Oven
  • Cuisine: American
  • Diet: Gluten Free


  • 1 pound Brussels sprouts, trimmed and halved
  • 1 tablespoon olive oil
  • 4 slices bacon, cut into lardon
  • ⅓ cup sliced shallot
  • 3 cloves garlic, minced
  • 1 tablespoon arrowroot starch
  • 1 cup full fat coconut milk 
  • 1/3 cup chicken broth
  • 1 tablespoon Dijon mustard 
  • ½ teaspoon dried thyme 
  • ¼ teaspoon nutmeg 
  • ¼ salt
  • ¼ black pepper
  • ½ cup parmesan cheese
  • ½ cup gruyere cheese


  1. Preheat an oven to 400 degrees.
  2. Toss the trimmed and halved Brussels sprouts in olive oil and liberally season with salt and pepper.  Transfer them to a 9×13 casserole dish and roast for 20-25 minutes until the edges start to brown and the sprouts are just tender. 
  3. Next, make the cheese sauce. Start by cooking the bacon over medium heat in a large skillet. Cook until crispy and then remove from the skillet to drain on paper towels. 
  4. Next, add the shallot and garlic to the skillet and cook until the shallot becomes translucent, around 3-4 minutes. 
  5. Next, stir in the arrowroot starch until well combined and cook for 1 minute. 
  6. Whisk in the coconut milk, chicken broth, dijon mustard, thyme, nutmeg, salt, pepper and let the sauce simmer until thickened, around 5-10 minutes. 
  7. Lastly, stir in the shredded parmesan cheese and half of the crispy bacon. Pour the sauce evenly over the Brussels sprouts. Top with shredded gruyere cheese and remaining crispy bacon. 
  8. Bake the casserole at 400 degrees until the cheese is melted and the sides are bubbly, around 10-15 minutes. Let the au gratin cool slightly before serving and enjoy!
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  1. Christine T says:

    I’ve made this for the past two Thanksgivings, leaving out the bacon for the vegetarians in my family. Both times, it has been the surprise hit of the side dishes. People love it and comment on how unexpectedly flavorful it is. So, so good.

  2. Made this for Thanksgiving and it was a hit! Everyone loved it and went for 2nds and 3rds! I roasted the Brussel sprouts and made the sauce a day in advance. Easy peasy! Thanks, Ashlea for a fantastic, crowd-pleasing recipe!

  3. I added portobello mushrooms and it was delicious!!!

  4. Libby Lasley says:

    Made these for my contribution to Thanksgiving and they were so good! Very little leftover! It was awesome to have a super easy recipe. I made the sauce and roasted the Brussels at home, took it to our destination, and then put the finishing touches on just before dinner. Thanks Ashlea for this delicious recipe!

  5. We made this for our Christmas dinner to go with prime rib last night. It was the perfect side dish for the meal, and we all loved it. Roasting the Brussels sprouts before adding the sauce kept them crispy and the cheesy, creamy sauce and bacon made it feel decadent- just what you want for a holiday meal!

    1. Ashlea Carver says:

      I’m so happy you enjoyed the recipe, Marla!

  6. We made this as a side on thanksgiving and it was so good! So cheesy and bacony on top of the brussel sprouts—honestly amazing! Would, and actually already have, recommended it!

    1. Ashlea Carver says:

      Love hearing that, Kaitlyn! Happy to hear that you loved this recipe!

  7. Creamy, delicious, and easy to make! Roasted the Brussels before our main course and finished them off right before eating. Definitely will make these again!

    1. Ashlea Carver says:

      Yay! So glad you loved them, Erin!

  8. Thank you so much for this recipe ! I would love to try it but make it in advance. What temp would I bake it at when reheating 25-30 min ?

    1. Ashlea Carver says:

      350 degrees should work, Maria!

  9. Rebecca Jones says:

    Followed this recipe for the Brussel Sprout Au Gratin to the letter and I love it. Thank you for sharing.

    1. Ashlea Carver says:

      You’re so welcome, Rebecca! Thank you for taking the time to leave a review!