Perfectly balanced and baked to golden perfection, this Cauliflower Au Gratin is a modern take on a French classic. It is easy enough for weeknight meals and decadent enough for your Thanksgiving Dinner Menu.
Cauliflower Au Gratin features tender cauliflower smothered in a rich, creamy parmesan sauce, all topped with melted cheese. If you’re looking for a healthier alternative to the traditional Potatoes Au Gratin, this recipe is sure to become a new favorite!
I love creating recipes using cauliflower because it is such a versatile vegetable! If you’re looking for similar cauliflower recipes to add to your Thanksgiving table, try my Mashed Cauliflower, Cauliflower Casserole, or Spicy Roasted Cauliflower. For low-carb variations of classic sides, check out my Cauliflower Potato Salad or Garlic Parmesan Cauliflower Rice.
How To Make Cauliflower Au Gratin
- Butter — I prefer to use unsalted butter since this dish already uses salt.
- Cauliflower — You’ll use one large head of cauliflower cut into small florets.
- Olive oil — I use extra virgin olive oil. Avocado or grapeseed oil will also work. You can also use melted butter.
- Onion — Use either a white or yellow onion, whichever you have on hand.
- Cream — If you like a rich sauce, use heavy cream; if you prefer a lighter sauce, use half and half. You can also use whole milk 2%.
- Parmesan — Finely grated parmesan cheese adds a nice nutty flavor.
- Seasoning — A blend of Italian seasoning, kosher salt, and black pepper.
- Shredded cheese — A cup of gruyere cheese, gouda cheese, swiss cheese or even cheddar cheese (sharp cheddar) makes this dish creamy and decadent.
I want to make it gluten-free and for this reason I didn’t use purpose flour.
Prepare the equipment:
- Before you begin, preheat the oven to 375°F (190°C).
- Then, grease a baking dish with butter or cooking spray.
Cook the cauliflower and onions:
- In a large pot, bring salted water to a boil.
- Add the cauliflower florets and cook for 5 to 7 minutes until it is fork tender but still slightly firm. Drain and set aside.
- In a skillet, heat the olive oil over medium heat and cook the onions for about five minutes until they become translucent and slightly caramelized. Turn off the heat and set aside.
Make the sauce:
- In a medium bowl, combine the heavy cream or half and half and grated parmesan.
- Stir or whisk in the Italian seasoning, salt, and pepper, mixing everything well.
Assemble the baking dish:
- Arrange the cooked cauliflower florets in the greased baking dish or a casserole dish.
- Spoon the caramelized onions on top of the cauliflower.
- Spread the creamy cheese sauce (cheese mixture) over the onions and cauliflower, making sure it is evenly distributed.
Top with cheese and bake:
- Evenly sprinkle the shredded gruyere or gouda cheese on top.
- Place the baking dish in your preheated oven and bake for 20-25 minutes until the cauliflower is fully tender and the cheese is bubbly and golden.
Cool and serve:
- Remove the baking dish from the oven and let it sit for a few minutes before serving.
- Once it is slightly cooled, the cauliflower au gratin is ready to serve and enjoy!
- For picture-worthy bubbly cheese, you can turn the broiler on high for the last 3 minutes. Just remember to keep an eye on it, as the broiler works quickly!
- I recommend shredding your own cheese, as it gives a much smoother, creamier finish than pre-shredded cheese.
- Cut your cauliflower florets into equal-sized pieces so they all cook evenly.
- Add an extra layer of flavor to this dish by roasting your cauliflower instead of boiling it. Follow my parmesan roasted cauliflower recipe for step-by-step- instructions.
- Allow the cauliflower au gratin to sit for several minutes before serving. This will help the sauce thicken just a bit and keep everything together when it’s time to serve.
How To Store Leftovers
- To Store: Allow the leftovers to cool and either cover your baking dish or place the leftovers in an airtight container. Then, store in the fridge for up to 4 days.
- To Freeze: While you can freeze the leftovers, cauliflower au gratin is best when it’s fresh, as the process of freezing and reheating may change the texture of the sauce. If you are going to freeze your leftovers, place them in a freezer-safe container and store for up to 2 weeks.
- To Reheat: I prefer to reheat leftover cauliflower au gratin in the oven at 350°F until it’s heated through. You can also reheat leftovers in the microwave.
What To Serve with Cauliflower Au Gratin
- Side salad: A crisp, fresh salad is a great complement to this rich, creamy dish. I recommend trying it with my Autumn beet orange salad or my simple arugula salad.
- Seasonal vegetables: I love serving fall-inspired seasonal produce together. This recipe would be delicious with other cruciferous veggies, like cabbage steaks or garlic parmesan roasted Brussels sprouts.
- Slow-roasted protein: The rich, complex flavors of the cauliflower au gratin pair wonderfully with a slow-roasted protein, such as my roasted pork tenderloin or easy roasted turkey leg.
- Thanksgiving dinner: Cauliflower au gratin is a low-carb twist on a holiday classic that goes great with similar healthy Thanksgiving sides, like my healthy green bean casserole and savory mashed sweet potatoes. Or it goes really well with Thanksgiving main dishes too like my turkey breast recipe, my roasted turkey and my roasted bone-in turkey breast.
- Cheese: Feel free to swap the cheese in this Cauliflower Au Gratin recipe for a different variety, or even mix a couple together for extra flavor! Some varieties that work well for this recipe are cheddar, Havarti, Colby-jack, and mozzarella.
- Spices: You can also add a little bit of nutmeg and even a teaspoon of Dijon mustard.
- Herbs: Add a savory, herby note to the sauce with fresh herbs such as rosemary, thyme, or oregano.
- Vegetables: If you want a veggie-packed recipe that little ones or picky eaters will love, it’s this one! You can also add other veggies like broccoli, zucchini, or leeks.
- Toppings: Garnish and toppings are a great way to add extra flavor and texture. Try topping your cauliflower au gratin with crumbled bacon, panko breadcrumbs or sliced scallions.
- Baking dish: The cauliflower au gratin is assembled in a 9×13 baking dish.
- Large pot: You’ll want a pot or Dutch oven large enough to boil the cauliflower.
- Cheese grater: Freshly shredded cheese works best for this recipe.
Frequently Asked Questions
Yes! Cauliflower au gratin is a great make-ahead dish for dinner parties or holidays. While I don’t recommend freezing this dish, you can make it in advance and keep it in the refrigerator for up to 3 days. Then, when you’re ready to cook and serve, place it in the oven at 350°F until it is heated through. I also recommend covering it with tinfoil to prevent the cheese from drying out.
The French term “au gratin” refers to the cooking method. It can be any dish that is topped with cheese or breadcrumbs and then heated in the oven or under the broiler until it is golden.
You certainly can! To save time on prep work, feel free to use frozen or pre-cut cauliflower. If you use frozen cauliflower, just be sure to drain it well after cooking so it doesn’t add excess water to the sauce.
- 1 teaspoon butter to grease a baking sheet
- large cauliflower head cut into small florets
- 1 tablespoon extra virgin olive oil
- 1 cup white or yellow onion finely chopped
- 1 cup heavy cream or half-half cream
- ½ cup finely grated parmesan
- ½ teaspoon Italian seasoning
- Salt and black pepper to taste
- 1 cup shredded gruyere or gouda cheese
- Preheat your oven to 375°F (190°C) and grease a baking dish (approximately 9×13 inches) with butter or cooking spray.
- In a large pot, bring water to a boil. Add a pinch of salt and the cauliflower florets. Cook the cauliflower for about 5-7 minutes or until they are tender but still slightly firm. Drain the cauliflower and set it aside.
- In a skillet, heat the olive oil over medium heat. Add the onions and sauté them until they become translucent and slightly caramelized, which should take about 5 minutes.
- In a medium bowl, add heavy cream or half-half cream, grated parmesan, Italian seasoning, salt and black pepper to taste. Mix everything well.
- Arrange cauliflower florets in the greased baking dish. Add the caramelized onions on top of the cauliflower and then, pour the creamy parmesan sauce over the cauliflower and onions. Make sure that the sauce is evenly distributed.
- Sprinkle the shredded gruyere or gouda cheese on top of the cauliflower.
- Place the baking dish in the preheated oven and bake for about 20-25 minutes or until the cauliflower is tender and the cheese is bubbly and golden brown. Enjoy!
- For extra bubbly cheese, turn on the broiler for the last 3 minutes.
- Shred your own cheese for a creamier texture.
- Cut cauliflower florets into equal-size pieces.
- Roast your cauliflower instead of boiling it.
- Allow the dish to sit for several minutes before serving.
- To Store: Keep in the refrigerator for up to 4 days in a covered baking dish or airtight container.
- To Freeze: Store in a freezer-safe container and freeze for up to 2 weeks.
- To Reheat: Reheat in the microwave or oven at 350°F.
Nutrition information is calculated using an ingredient database and should be considered an estimate.