Brussels Sprouts au Gratin Keto Recipe

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Published: 01/17/2019 | Updated: 02/07/2024

This Brussel Sprouts au Gratin keto recipe is the perfect low-carb side dish. Crispy, roasted brussels sprouts in a cheesy sauce that will make even brussels sprouts haters fall in love with this easy recipe!

roasted brussels sprouts with melted cheese in baking dish

I’m a fan of Brussel sprouts in nearly any form,but especially when they’re roasted! Brussel sprouts tossed with olive oil and sea salt, or even kosher salt, then roasted at high heat until they caramelize pretty much perfection in my eyes.

This recipe for Brussel sprouts au gratin kicks it up another notch, though. The best part is that these are low-carb, so they fit in perfectly with the keto eating plan!

These come in at 7 grams net carbs for a pretty large serving. You could always decrease your serving size to use up even fewer carbs, but I can never resist these, so I just plan my day accordingly!

How to Make Brussels Sprouts

There are 3 main ways to make brussels sprouts because we’re not even going to go into microwaving brussels sprouts. Nope, just don’t do that.

  1. Roasting Brussels Sprouts- This is by far my favorite way to make brussels sprouts. I normally cook them for about 40-45 minutes at 425 degrees with olive oil and sea salt. They taste like candy! For this recipe, I used the same method, just shortened my time to about 15 minutes. I just wanted them to begin to caramelize but not cook the whole way through since they still had to cook for another 25 minutes once the casserole was assembled.
  2. Frying Brussels Sprouts- Sometimes, I will pull out my cast iron skillet, heat up some olive oil, and fry the Brussel sprouts with sesame seeds. I’ve also started using my air fryer in place of pan-frying, and they turned out amazing that way too.
  3. Boiling brussels sprouts- I’ll be honest, this is my least favorite way to cook brussels sprouts. I like mine crispy and caramelized, and you can just achieve that with boiling. But if it’s your preferred cooking method, just boil some water, season with salt, and boil your brussels sprouts until they are fork-tender. For this recipe, you’ll just want to let them boil for about 3-5 minutes.

brussels sprouts au gratin with a serving missing from the baking dish

How to Make Brussels Sprouts au Gratin

This is such a simple dish to make and goes perfectly with roast pork or grilled chicken. You can even roast your brussels sprouts ahead of time and then just assemble the rest of the dish when you’re ready to bake it.

To start, use a knife to cut off the stem. Discard the stem and any of the outer leaves that fall off. Then cut each brussels sprout in half vertically.

In a large mixing bowl , mix the brussels sprouts with olive oil, salt, black pepper, and garlic powder. Toss till they’re evenly coated and then spread on a baking sheet. Bake for about 15 minutes at 400 degrees until they start to brown and caramelize.

Remove the cookie sheet from the oven, but leave the oven turned on to 400 degrees.

Transfer the brussels sprouts back to the mixing bowl and toss with the heavy cream, 1/2 cup of the cheddar cheese, and 1/2 cup of the parmesan. Toss the cream mixture well and transfer to a greased 3-quart baking dish.

Top the brussels sprouts with the remaining cheese sauce and then bake at 400 for about 25 minutes. You want your cheese to be nice and golden brown and be able to see the creamy sauce below bubbling.

It will thicken as it sits, but you can serve immediately too!

brussel sprouts au gratin with melted cheese in a baking dish

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Brussels Sprouts au Gratin Keto Recipe

roasted brussels sprouts with melted cheese in baking dish
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5 from 1 vote

Brussels Sprouts au Gratin

Roasted brussels sprouts are baked in a cheesy sauce for this delicious low-carb side dish. 
Prep Time10 minutes
Cook Time40 minutes
Total Time50 minutes
Course: Side Dish
Cuisine: American
Keyword: brussels sprouts au gratin, Brussels sprouts keto, brussels sprouts recipe
Servings: 6
Calories: 274kcal
Author: Natalie Dixon


  • 1.5 lbs Brussels sprouts
  • 2 Tbsp. Olive Oil
  • Sea Salt
  • Ground Pepper
  • 1 tsp. Garlic powder minced
  • 3/4 cup Heavy Cream
  • 1 cup Sharp Cheddar Cheese grated
  • 1 cup Parmesan Cheese grated


  • Preheat oven to 400 degrees. Grease a 3-quart baking dish and set aside. 
  • Remove stems and outer leaves of brussels sprouts. Cut large brussels sprouts in half.
  • In a large mixing bowl, toss brussels sprouts with olive oil, minced garlic and a sprinkle of sea salt and pepper. Spread brussels sprouts on baking sheet and roast in preheated oven for about 15 minutes until they start to caramelize. 
  • Remove from baking sheet and transfer brussels sprouts back to large mixing bowl. Add heavy cream, 1/2 cup cheddar cheese and 1/2 cup parmesan cheese. Stir well to combine.  
  • Pour brussels sprouts mixture into 3-quart baking dish. Top with remaining parmesan and cheddar cheeses. Bake at 400 for about 25 minutes until it is bubbly and the cheese is starting to brown. 


You can substitute the cheddar cheese with the cheese of your preference. Other good options would be gruyere or swiss.
I'm a fan of roasted brussels sprouts, but you could boil them instead if you prefer. Just omit the step where you roast them in the oven before assembling the casserole. Instead, boil a pot of salted water. Add the brussels sprouts to the water for about 3-5 minutes. Drain well and then add back to the mixing bowl to toss with the cream and cheese.

brussel sprouts au gratin

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