Brussels Sprouts au Gratin with Pancetta and Walnuts

December 9, 2019 By Whip & Wander 34 Comments

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Melty, cheesy delicious

Have you ever been asked to bring a dish over for the holidays or another special occasion and you want to make it look like you really pulled out all the stops? Or maybe you just have a deep appreciation for vegetables disguised as vessels for cheese. In either case, this Brussels Sprouts au Gratin with Pancetta and Walnuts will fit the bill nicely.

These Brussels sprouts are tossed in garlic oil before taking a quick turn in the oven to roast until lightly crisp, then drenched in a creamy sauce and 3 types of cheese (yes, 3!) and popped back in the oven to tenderize into a melty pool of cheesy deliciousness. After a final turn in the oven, they’re finished with a mix of pancetta, thyme, and toasted walnuts. The resulting dish is both creamy and rich with layers of texture to spare.

What makes Brussels Sprouts au Gratin so creamy and rich

This Brussels Sprouts au Gratin is extra creamy thanks to a simple blend of half & half, Dijon mustard, and egg which work to emulsify and bind everything together into a rich sauce that thickens as it cooks. The sauce is seasoned with a simple mix of sea salt, cracked pepper, red pepper, thyme, and a pinch of nutmeg and then topped with a blend of gruyere, white cheddar, and parmesan to become the ultimate creamy + cheesy indulgence.

2 ways to toast the nuts

Toasting nuts is a simple way to intensify flavors and improve their crunchy texture. These are my 2 favorite ways to toast them:

Stovetop – This is my preferred way to toast small batches of nuts, like the amount used in this dish. Simply heat nuts in a dry skillet over medium heat, stirring frequently as they begin to brown and intensify in smell. Once toasted, remove the nuts from the pan so that they do not continue to cook. The whole process should take about 5 minutes.
Oven – This is my preferred way to toast larger batches of nuts, but you can also do small batches this way if you prefer. Cover a baking sheet with parchment paper, then top with dry nuts. I like to toast at a lower temperature, usually 300 degrees F (150 C) for around 25 minutes, but you can bump this as high as 350 degrees F (180 C) for a shorter amount of time (usually around 15 minutes) if you’re balancing other dishes in the oven at the same time.

For both methods, keep in mind that nuts can go from a lovely golden brown to burnt very quickly, so you’ll want to keep a close eye on them as they cook. You can feel free to add herbs or spices as you cook the nuts, but oil is not necessary as the nuts will produce their own as they cook.

My favorite nut choice for this Brussels Sprouts au Gratin is walnuts, which I toast with a small amount of additional thyme. If you don’t have walnuts on hand, almonds, pecans, and hazelnuts are all lovely alternatives.

Storage and reheating

These Brussels Sprouts au Gratin with Pancetta and Walnuts can be stored in an airtight container for up to 3-4 days. You can reheat in an oven-safe dish at 350 degrees F (180 C) until hot (If you find that your nuts are in danger of over-toasting you can cover the dish in foil when baking). For smaller portions, reheat in a microwave-safe dish for 3 minutes, stir, and heat at additional 30-minute intervals as needed.

Do you have to use a cast iron pan?

No, but its my favorite option for this Brussels Sprouts au Gratin recipe because it crisps the Brussels sprouts beautifully. If you do not have a cast-iron pan, you can use a large oven-safe casserole dish instead.

Tools needed to make this recipe

a cutting board
a chef’s knife
a large cast-iron pan or large oven-safe casserole dish
a medium saute pan
a spatula or wooden spoon
a whisk
measuring cups and measuring spoons
a medium prep bowl
a small dish to reserve pancetta then walnuts in
a cheese grater (unless you buy pre-shredded cheese)

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A note for special diets

This Brussels Sprouts au Gratin with Pancetta and Walnuts is grain-free, gluten-free, low-carb, and friendly for Keto diets.

This dish can also be really friendly for those following a low-lactose diet. The Gruyère, sharp white cheddar, and parmesan all generally contain less than 0.5g lactose per serving of cheese. For the half & half, this option is lactose-free and found at Whole Foods.