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.

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.

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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.

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.

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.

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!

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.