Brussels Sprouts Au Gratin

This Brussels Sprouts Au Gratin has to be the best way I’ve been enjoying Brussels sprouts lately! We love plain roasted Brussels sprouts in this house and this is like a combination of roasted Brussels sprouts and mac and cheese (sans the noodles). Especially with the cooler weather, this is a really comforting, warm side that I’m sure everyone at your table will love!

What is Au Gratin?

Basically Au Gratin is any time a dish has a browned top crust, most of the time the topping being breadcrumbs or cheese. Potatoes au gratin is probably where you have mostly commonly heard the term. Potatoes au gratin are the same as scalloped potatoes and are thin slices of potatoes cooked in a creamy cheese sauce and topped with more cheese that is then browned and cooked under the broiler or oven. So in this case, we are substituting potatoes for Brussels sprouts! And honestly? I think I like it better!

How to Make Brussels Sprouts Au Gratin

First things first, I start by cooking up my bacon. Now technically the bacon really isn’t necessary, but in my book it is! If you wanted to sub turkey bacon or omit it completely, you will need to add some oil to the recipe to cook the Brussels sprouts in. I recommend using a combination of butter and a high heat oil like avocado oil.

While my bacon is cooking, I start by trimming my Brussels Sprouts. I trim up the woody stems and remove the outer leaves. Then using a sharp knife, I cut the Brussels sprouts lengthwise into about 1/4 inch wide pieces. This helps to ensure that the Brussels Sprouts cook evenly in the au gratin.

Once the bacon is cooked, I removed the bacon with a slotted spoon and set it aside for later, leaving the grease in the case iron. Then I added the Brussels sprouts into the bacon grease and let then get browned for about 8 minutes. Make sure you season with a bit of salt and pepper at this stage!

After the Brussels got a nice char on them in the bacon grease, I gently stirred in the minced garlic and let it cook for about 2 minutes.

Then we get to the best part: the sauce! All you do is turn off the heat on your stove and mix in heavy cream, half of both cheeses, and the bacon bits from earlier. Be sure to give it a taste and season with more salt and pepper if needed. Once everything is well incorporated, I add the remaining cheese on top of the mixture and pop it in a 400°F oven. You’ll let everything cook for about 10-12 minutes or until the sides are bubbly and the top is getting a nice brown on it.

Choosing the Dish for the Brussels Sprouts Au Gratin

I chose a cast iron to cook the Brussels sprouts au gratin in, and that is what I recommend; however, you have other options. You could also cook it in a stainless steel pan that is safe for the oven (for example, I really like my stainless steel All-Clad pan as it can also go from stove to oven):

If you don’t own a cast iron pan or a pan that is safe to go in the oven, you could alternatively cook the bacon and Brussels sprouts in whatever pan you have, then add the cream and cheese and get it melted before transferring to a small casserole dish that is oven safe. I have this au gratin dish from Le Cruset that this dish would look really nice in! But cooking it on the stove and then in the oven all in the same dish obviously makes clean-up much easier!

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