Roasted Cauliflower Au Gratin

This Oven Roasted Cauliflower Au Gratin recipe is a take on the classic potato side dish - perfect to serve on Thanksgiving or with a chicken or steak dinner

Roasted Cauliflower Au Gratin (or simply Cauliflower Gratin) is a new way to enjoy more heart-healthy cruciferous vegetables – aka cauliflower and broccoli! It’s a lower-carb spin on the traditional potato gratin. Cauliflower still has carbs, but only about 140g for a whole cauliflower head versus 150g for one potato. It’s a modern take on a classic that’s perfect for Thanksgiving dinner!

How do you make cauliflower gratin?

Start by roasting the cauliflower int the oven on a baking sheet lined with parchment paper. You can also roast it in the casserole dish. However spreading it out helps to crisp up the cauliflower florets. Drizzle it with olive oil, then season with garlic powder, salt and pepper. Alternatively you can boil the cauliflower, but roasting it gives the dish a better flavor.

Roasted cauliflower drizzled with a cheesy creamy sauce melted all over is also a great way to get your kids to eat more cauliflower. Heck, it’s a great way to get adults to eat more cauliflower, and I’m all about that! Pair up this cauliflower au gratin side dish with steak or seared lamb for a slam dunk, well-rounded meal!

While the cauliflower is roasting, you can make a bechamel sauce by whisking butter and flour, and then gradually adding warm milk, nutmeg and cheese. It creates a simple delicious cheesy sauce that is iconic of gratin recipes. When the cauliflower is done roasting, transfer it to a casserole dish and pour the sauce over the cauliflower.

You can give it a gentle stir or leave it as is. Then sprinkle panko breadcrumbs and the remaining cheese on top and return to the oven until the top is golden brown and whole dish is bubbling.

Sprinkle the finished cauliflower au gratin it with some fresh parsley, and serve it while it’s hot with a main dish.

Tips for making cauliflower au gratin

Use a hard cheese to get a crispy edge. This includes gruyere, which is what’s traditionally used, but also parmesan cheese works well. Soft cheeses like mozzarella and Gouda are great for getting a melted top.
Add more vegetables for more color and variety. This method works really well with other vegetables. I recommend adding broccoli and carrots to it.
Let a cauliflower gratin sit for a few minutes before serving. That will allow everything to set properly so it doesn’t fall apart when you serve it. Plus, it won’t be as piping hot then!

Individual portion of the cauliflower au gratin spooned into a small bowl

If you’re looking for an alternative to potato gratin or Baked Macaroni and Cheese with extra veggies, you’ve got to try this cauliflower gratin recipe. It elevates the simple cauliflower vegetable into a cheesy crave-worthy dish complete with crispy bits of roasted cheese and breadcrumbs!

This cauliflower au gratin is a modern take on potato au gratin with less carbs and calories. Roasting the cauliflower adds a wonderful flavor that pairs well with the nutty creamy sauce. It’s a delicious side dish recipe that’s cheesy, easy and pleases everyone! It’s simple enough for weeknights, but also fun to serve with a big meal like Thanksgiving dinner.

Ingredients

1 3-pound head cauliflower, cut into florets
1 tablespoon olive oil
½ teaspoon garlic powder
½ teaspoon salt
¼ teaspoon pepper
2 tablespoons unsalted butter
2 tablespoons all-purpose flour
1 1/2 cups milk room temperature
1/4 teaspoon grated nutmeg
1 cup freshly grated Gruyere divided
1/4 cup panko breadcrumbs

Instructions

Preheat the oven to 425°F.
Place the cauliflower florets on a baking sheet. Drizzle with olive oil, then season with garlic powder, salt and pepper. Toss to coat, then roast in the oven for 20 minutes, turning at the halfway point.
Meanwhile, melt the butter in a small saucepan over low heat. Add the flour, stirring constantly with a whisk or wooden spoon until well blended. Slowly whisk in the warm milk and stir until the mixture thickens, about 3-5 minutes.
Remove from heat, season with nutmeg and mix in half the cheese.
Transfer the roasted cauliflower from a baking pan to an 8x11 casserole dish. Pour the sauce evenly on top. Then sprinkle with the remaining gruyere and panko breadcrumbs.
Low the oven temperature to 375°F and bake until the top is browned and bubbly, about 20-25 minutes.

Notes

Storage: Store any leftovers in an airtight container. They will last up to 3 days in the fridge, but the consistency is best if eaten the first day. To reheat, place in the microwave for a minute or in the oven at 350°F for 5 minutes. I would not recommend freezing the dish though.

Substitutes: For best results, follow the recipe as is. However here are some common substitutes that would work well in this recipe.

Use other types of shredded cheese in place of gruyere if you'd prefer. Since this recipe is French in origin, gruyere is the traditional cheese use, but it works well with mozzarella and/or parmesan cheese.
Instead of milk, you can use dairy-free milk like unsweetened almond milk.
Instead of butter, you can use olive oil.
To make it gluten-free, you can use almond flour or a GF 1:1 mix. Here's an excellent post on how to make gluten-free roux.

Nutritional Data: The information below is an automated estimate. It could vary based on cooking methods and ingredients used.