Move on over, potato, ‘cause there’s a new favorite side dish in town, and it’s called Cauliflower Au Gratin. This cauliflower casserole is loaded with creamy, baked-to-perfection parmesan cheese and a delicate thick roux.
Best of all, Cauliflower Au Gratin is the perfect replacement for your ordinary potato side dish; it’s lower in carbs but bursting with flavor!
And just like roasted or mashed potatoes, Cauliflower Au Gratin can be paired with all sorts of meals, from chicken and pork to fish or beef. It’s ready to go in less than an hour with very little prep, making it the perfect option for a weekend dinner. But there’s no reason to stop there; it looks and tastes as amazing dressed up as dressed down, perfect as a comforting side dish.
- cauliflower – before you get started on this cauliflower gratin casserole, you need to cook your cauliflower. It needs to be roasted (recommended) or steamed in order to turn it into a casserole.
- butter – Real butter has the best flavor. Do not add margarine here unless you want to alter the taste.
- grated Parmesan cheese – I like freshly grated Parmesan cheese myself.
- fresh parsley (optional) – lets face it, cauliflower can often look like a boring dish, so adding a few fresh herbs spices up the look if you are adding to a Thanksgiving table. Its not necessary for taste.
- bread crumbs – If you want to remove the breadcrumbs, it sorta takes it away from the “au gratin” category, but if you add a nice layer of Parmesan cheese on top, it can still give you that crispy taste.
Add Some Seafood
Creamy cauliflower is the star of the show but you can also add lobster, crab, mahi mahi or even favorites like cooked chicken for a full meal.
- Avoid mushy cauliflower: vegetables, including cauliflower, consist of a surprisingly high percentage of water, which in turn can make your finished casserole mushy. To avoid this, I suggest pre-cooking your cauliflower by roasting it for about 10 minutes in the oven at 450 degrees.
- This cauliflower side dish is so easy to load up! Add other types of cheeses (I like Cheddar on my cauliflower), bacon bits, ham, or bites of freshly chopped green onions.
- Creamy cauliflower is the star of the show but you can also add lobster, crab, mahi mahi or even shrimp to make this casserole a full meal.
How to make Cauliflower Au Gratin
Make sure to check out the printable recipe card for full step by step instructions and ingredients.
- Preheat the oven to 425 and grease a baking dish with nonstick cooking spray.
- Spread pre-cooked cauliflower pieces in a baking dish. Set aside.
- In a saucepan, over low heat, melt butter.
- Increase heat to medium and add flour and whisk until bubbly.
- Stir in heavy whipping cream and heat over medium heat, whisking constantly until thick.
- Remove from heat and stir in cheese, salt, cayenne pepper and nutmeg.
- Pour roux over cauliflower, covering as much of the top as possible.
- Top with grated Parmesan cheese and bread crumbs.
- Bake casserole for 25 minutes.
- Add bits of chopped fresh parsley before serving for color.
Please note that making Roux can be really difficult for some and it can thicken if heated too much and too quickly. You can add up to 1 more cup of heavy whipping cream to thin out roux. Just remember you cannot walk away from the pan while making roux. It moves quick.
Au gratin, which translates from French as “by grating” is a method of cooking in which breadcrumbs, grated cheese, or both are sprinkled over a dish and then baked until browned. While most people are familiar with potatoes au gratin, as you’ll soon find out, cauliflower makes a perfect and healthy substitute for potatoes with all the amazing au gratin flavor and texture of breadcrumbs and golden browned cheese, without as many carbs!
Basically anything that you would pair with a potato side would be a good accompaniment to this Cauliflower Casserole. Here are some of my favorite dishes with which Cauliflower Au Gratin would taste amazing:
Baked Garlic Parmesan Chicken
Asparagus Stuffed Chicken
Oven-Roasted Lamb Chops
Slow Cooker Pepper Steak
I wouldn’t recommend using frozen cauliflower in this dish, but if that’s all you’ve got, go for it. Cook the cauliflower until it is just slightly tender, then proceed with the rest of the recipe. Just be careful to REMOVE EXCESS MOISTURE!
Cauliflower Casserole can be frozen in an airtight container for as long as three months. Allow it to thaw in the fridge overnight, then cover with aluminum foil and warm in the oven until heated through and bubbling.
Unfortunately the roux in this dish contains flour, which helps thicken the roux. This isn’t always replaceable in keto friendly and low carb flours like almond flour and won’t thicken the same. However, it doesn’t mean it wont be delicious so its worth a shot if you are looking to convert recipes.
Top with chives, sour cream, green onions and bacon for a loaded up dish.
- Broccoli Cauliflower Casserole – This rice based casserole is filling and delicious with a combination of broccoli, cauliflower and cheese. Just add chicken for a full meal.
- Cauliflower Mashed Potatoes – Nothing wrong with a bit of mashed potatoes, but this cauliflower mashed is perfect for a great cauliflower side dish that is creamy and delicious
- Keto Cauliflower Casserole – This cauliflower casserole skips the bread and is low carb friendly
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Parmesan Cauliflower Au Gratin
- 1 large head cauliflower - steamed/cooked and broken into pieces
- 6 tablespoons butter
- 1/2 cup flour
- 1 1/2 cups Heavy Whipping cream
- 1/3 cup grated Parmesan cheese
- 1 teaspoon salt
- pinch cayenne pepper
- pinch nutmeg
- 2 tablespoons bread crumbs
- 2 tablespoons shredded Parmesan cheese
- chopped fresh parsley - optional
- Before getting started, cauliflower must be roasted or steamed. This recipe relies on pre-cooked cauliflower.
- Preheat oven to 425 and grease a baking dish with nonstick cooking spray.
- Spread cauliflower bits in baking dish. Set aside.
- In a saucepan, over low heat, melt 6 tablespoons of butter.
- Increase stove heat to medium and add flour and whisk until bubbly, which will happen pretty quickly.
- Stir in heavy whipping cream and continue to heat over medium heat, whisking constantly until thick. This usually takes just a few minutes.
- Remove roux from heat and stir in grated Parmesan cheese, salt, cayenne pepper and nutmeg.
- Please note that making Roux can be really difficult for some and it can thicken if heated too much and too quickly. You can add up to 1 more cup of heavy whipping cream should you need to, to thin out the roux.
- Pour roux over top of cauliflower.
- Sprinkle on additional Parmesan cheese as a topping and a bit of finely ground bread crumbs,
- Bake casserole for 25 minutes.
- Top with chopped fresh parsley before serving.
I would not recommend freezing as the heavy whipping cream may separate and the cauliflower may water on defrost. This one is best made fresh.
How to Steam CauliflowerYou can pre-roast your cauliflower to give it a really robust taste and to keep out moisture (recommended), rice it out, puree your cauliflower, or steam cauliflower. Steaming introduces a lot more water to this vegetable and can make the final casserole with too much moisture but still can work in a pinch of time. Just be sure to drain cauliflower properly before turning into a casserole.
- Use a 2 tier steamer
- Use a pan steamer which adds a secondary pot to the stove so you can steam veggies right on the stove, very versatile
- Purchase steam in the bag cauliflower – just remove excess moisture very well