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This Golden Cauliflower Gratin with Hazelnuts is just another proof offering for my undying adoration of gratins. I love them. Everyone else seems to love them. And so. I throw out lots of fun ways to “gratin” here on MKL – and this one is especially great for fall. The warm, toasted notes from hazelnuts is really delicious in this recipe, but you can substitute walnuts if you like. Those are pretty great tasting here as well. Up to you!

If you like the looks of this cauliflower gratin with hazelnuts, you might also enjoy our Sweet Potato and Pineapple gratin (I know, trust me here), or this Hasselback Potato Gratin. Also we’ve got a tasty roasted leeks recipe that is absolutely worth your time – at least read the post and see what you think! And for one more veggie side dish option, I’ve got a really easy and homey-feeling cheesy asparagus that I think you’ll want around for a rainy day.

Golden Cauliflower Gratin with Hazelnuts
Golden Cauliflower Gratin with Hazelnuts
Golden Cauliflower Gratin with Hazelnuts

What is a Gratin?

Sometimes referred to as gratinée or au gratin, gratins are simply French-inspired (the technique is French, that is) dishes of layered-and-baked sundries, covered in some sort of crispy topping, such as breadcrumbs or cheese, and lightly browned in the oven.

The baking of a gratin typically always involves a shallow dish or pan, to allow for maximum spreading and hence, browning, and the crispiness on top is almost always achieved from the help of ample cheese and/or the aforementioned breadcrumbs. The term “gratin” itself is lovably flexible and, while it is probably most often associated with potatoes au gratin, it could technically even be applied to baked mac and cheese, just so long as there are crunchy breadcrumbs on top.

Today, I’m taking some license with that part, and swapping in a handful of toasty, crunchy hazelnuts for the coating of breadcrumbs, because I just love them so. Plus, in addition to using olive oil for the roux instead of butter, it’s a small swap that lightens the whole thing just a smidge.

This cauliflower gratin with hazelnuts recipe is a nice addition to your arsenal of heavy-hitting vegetable side dishes. It truly complements almost anything and comes together easily, all in one pan (we love that!). I mean, you could create the sauce in a separate pan, but there’s really no need. One pan works fine (a My Kitchen Little victory).

The golden glow of the turmeric is an unexpected addition in a gratin, and I personally can’t get enough of that toasted hazelnut crunch on top; the perfect finishing touch. Save for burning it, this baked cauliflower gratin is a dish that is almost impossible to mess up, and even if you play around with the various amounts and components, you’ll still more than likely end up with one very satisfying, delectable gratin.

Golden Cauliflower Gratin with Hazelnuts

What’s in this golden cauliflower gratin with hazelnuts?

The ingredients that go in this “golden” cauliflower gratin with hazelnuts are simple and straightforward – there are no real zingers here, no oddballs. The onion deepens the flavor and adds an addictive allium note like only an onion can. All-purpose flour lends its thickening genius to things, helping us build a lovely, creamy sauce. Nutmeg adds a warm interest to the flavor of the whole dish, and while it’s quite traditional in creamy dishes – I actually like it with the hazelnuts. They are BEST friends.

And the turmeric? It just has this glowy, gleamy, wonderful effect on anything it touches (your countertops as well, so watch out for that). The very subtle earthiness it lends to recipes is just lovely, I think. Pick the cheese you like as well, for this cauliflower gratin with hazelnuts, as Gruyere tends to me a smidge pricier. Swiss works well, too. If you have parmesan, that is great when paired with Swiss cheese as a way of mimicking the nuttiness of a good Gruyere.

  • 4 tablespoons olive oil, divided, plus more as needed
  • 1 small sweet onion, diced
  • 1 large head cauliflower cut into bite-sized florets, about 3 cups
  • Salt and pepper to taste
  • 1/4 cup all-purpose flour
  • 1.5 to 2 cups milk
  • 1/2 cup sour cream
  • 1/2 teaspoon freshly grated nutmeg
  • 1/2 teaspoon ground turmeric
  • 2.5 cups freshly shredded Swiss or Gruyere cheese, plus extra for topping
  • 1/3 cup chopped toasted hazelnuts (see note for toasting tip)

How to make this cauliflower gratin with hazelnuts

  1. Preheat your oven to 400 degrees F.
  2. Place a large, oven-safe skillet over medium heat and add 2 tablespoons of the olive oil. When it’s hot, add the onion and cauliflower and season generously with salt and pepper. Cook, stirring frequently, until the veggies are tender; about 8 to 10 minutes.
  3. Add 2 more tablespoons of oil to the pan and sprinkle over the flour. Stir to combine and to cook for about a minute more. Add the milk, stirring/whisking constantly as you do, and allow the mixture to gently bubble and to prevent lumps. Please feel free to add more milk if it looks/feels dry. You want the mixture to be thick and creamy – think mac and cheese. Reduce the heat after it bubbles for you (it should thicken significantly).  
  4. Add the sour cream, nutmeg, turmeric, and cheese. Stir very well to combine everything. Taste for seasoning and add more salt/pepper, as needed.
  5. Top the skillet with a little more cheese and place in the oven. Bake the gratin until hot and bubbly, and the cauliflower is lightly golden on top about 15 minutes.
  6. Serve the gratin with the chopped hazelnuts sprinkled over top.
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Golden Cauliflower Gratin with Hazelnuts

Golden Cauliflower Gratin with Hazelnuts
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The earthy turmeric gives this gratin a distinctive golden glow, and the hazelnuts offer a fantastic crunch – a great textural contrast to all that creaminess. I like to sneak a little sour cream into this gratin as well. The flavor and creaminess that just a little bit adds is fantastic here. This is a quick bake time, compared to many gratins, because everything is cooked before the pan even goes into the oven.

Ingredients

Units Scale
  • 4 tablespoons olive oil, divided, plus more as needed
  • 1 small sweet onion, diced
  • 1 large head cauliflower cut into bite-sized florets, about 3 cups
  • Salt and pepper to taste
  • 1/4 cup all-purpose flour
  • 1.5 to 2 cups milk
  • 1/2 cup sour cream
  • 1/2 teaspoon freshly grated nutmeg
  • 1/2 teaspoon ground turmeric
  • 2.5 cups freshly shredded Swiss or Gruyere cheese, plus extra for topping
  • 1/3 cup chopped toasted hazelnuts (see note for toasting tip)

Instructions

  1. Preheat your oven to 400 degrees F.
  2. Place a large, oven-safe skillet over medium heat and add 2 tablespoons of the olive oil. When it’s hot, add the onion and cauliflower and season generously with salt and pepper. Cook, stirring frequently, until the veggies are tender; about 8 to 10 minutes.

  3. Add 2 more tablespoons of oil to the pan and sprinkle over the flour. Stir to combine and to cook for about a minute more. Add the milk, stirring/whisking constantly as you do, and allow the mixture to gently bubble and to prevent lumps. Please feel free to add more milk if it looks/feels dry. You want the mixture to be thick and creamy – think mac and cheese. Reduce the heat after it bubbles for you (it should thicken significantly).  

  4. Add the sour cream, nutmeg, turmeric, and cheese. Stir very well to combine everything. Taste for seasoning and add more salt/pepper, as needed.
  5. Top the skillet with a little more cheese and place in the oven. Bake the gratin until hot and bubbly, and the cauliflower is lightly golden on top about 15 minutes.
  6. Serve the gratin with the chopped hazelnuts sprinkled over top.

Notes

To toast your hazelnuts, just put them on a sheet pan in a 350-degree oven for 6 to 8 minutes (sometimes a little longer, depending on size). If they happen to have skins, remove those as best you can before toasting.