Allow me to introduce you to this cheesy Cauliflower au Gratin, your new favorite easy low-carb recipe! Roasted cauliflower is coated in a sauce made with Gruyere and Parmesan cheese, then baked in the oven. Serve this healthy vegetarian casserole for Thanksgiving or any holiday dinner when you want to impress!
To say this Cauliflower au Gratin is out-of-this-world delicious would be the understatement of the year.
Yes. I’m being 1000% real here.
Even my picky cauliflower recipe hubby went back for seconds and thirds of this low-carb casserole!
(Something this Mashed Cauliflower and Whole Roasted Cauliflower came close to doing, but didn’t quite accomplish.)
And it totally makes sense.
Cauliflower is cut into bite-sized florets, roasted, then covered in a creamy Gruyere cheese sauce that is to DIE for.
A mixture of Parmesan cheese and breadcrumbs are then sprinkled on top and broiled until golden and crispy.
The rich and savory sauce paired with the light and low-carb cauliflower will leave you satisfied but not overstuffed.
Leaving you more room in your tummy to enjoy those yummy Thanksgiving side dishes and pumpkin pie.
What Does “au Gratin” Mean?
“Au Gratin” is a French word that simply means “by grating.” It normally means the dish is topped with grated cheese and/or breadcrumbs and then baked until browned. Popular variations are made with potatoes or cauliflower, sometimes referred to as simply “Potato Gratin” or “Cauliflower Gratin”.
Ingredients
The simple ingredients you need to make this cauliflower gratin recipe include:
- Cauliflower. You’ll need one large head, about 3 pounds, to give you roughly 5 cups of chopped florets.
- Flour. If you’re gluten-free, you can use a 1-to-1 blend.
- Milk. Cashew milk was tested in this recipe to reduce the amount of dairy while keeping things thick. Heavy cream or regular milk may also be substituted. Almond milk is too thin, and the taste of coconut milk will be overpowering.
- Shredded Cheese. The best shredded cheese for this recipe is Gruyere. Shredded mozzarella, mild cheddar, or white cheddar will also work.
- Parmesan. A little bit of Parmesan cheese is mixed into the sauce as well as sprinkled on top for a delightful crunch.
- Breadcrumbs. These add to the crunchy texture. If keto, either leave them out or substitute with pork-rind crumbs if on a keto diet.
- Spices & Herbs. A hint of dried thyme and a bit of ground coriander accent the cheeses selected. Feel free to get a little creative and try out dried rosemary and tarragon or a sprinkle of ground nutmeg, instead.
How to Make a Cauliflower au Gratin
The basic steps for making cauliflower gratin are simple to follow. Please see the recipe card below for more detailed ingredient amounts.
Prepare & Roast Cauliflower
When cutting the cauliflower into florets, you’ll want to make them as close to the same size as possible.
Larger florets will give you a crunchier bite while smaller florets tend to overcook easily. So it’s best if you make your florets no smaller than about 1-inch in size.
If you look at other cauliflower gratin recipes, you will notice a variety of methods for pre-cooking the cauliflower.
Some call for boiling, others steaming, but the best way to do it is to roast cauliflower. (Much like in this Roasted Cauliflower recipe.)
Baking brings out the natural and subtle sweetness of the cauliflower. It also gives it a delightful crunch that boiling and steaming just can’t do.
Toss the cauliflower florets in oil, salt, and pepper. Then bake in a 13 by 9-inch baking dish at 450°F for 15-20 minutes.
Make the Creamy Cheese Sauce
The basic process for making the creamy cheese sauce is similar to making a cream gravy from scratch.
- You’ll first start by whisking together a bit of garlic, butter, and flour together in a skillet over medium heat. (Step 1 & 2 below.)
- After a few minutes a thick paste will form.
- It is extremely important you whisk it over heat until it is nice and thick. This paste acts as the binder for the sauce.
- Warmed or room temperature milk is then slowly added in, about ¼-cup at a time. (Step 3 below.)
- Similar to risotto, you want the liquid to be warm so it does not bring down the temperature of the sauce.
- Heat it in the microwave for 30 seconds, or leave it out at room temperature for 30 minutes before cooking.
- After each addition of milk, whisk the sauce until it is smooth and begins to thicken.
- Repeat this process over the course of 3-5 minutes.
- Once all of the milk is added, mix in the shredded cheese, seasonings, and half of the Parmesan cheese. (Step 4 below.)
- Stir until well combined.
Assemble the Casserole
Pour the sauce over the baked cauliflower and toss to combine.
Mix together the remaining Parmesan cheese and breadcrumbs in a small bowl and sprinkle over the cauliflower.
Reduce the oven temperature to 400°F and return the cauliflower dish to the oven for 20-25 minutes.
Dietary Modifications
The recipe you’ll find below is already vegetarian and low-carb as written. Here are some adjustments and substitutions you can make to help it fit your other dietary requirements:
- Keto – Omit the breadcrumbs, or use a low-carb alternative such as pork-rind crumbs.
- Gluten-Free – Select gluten-free breadcrumbs and flour.
- Dairy-Free – Choose an oat or cashew milk.
Meal Prep and Storage
- To Prep-Ahead: Follow all of the instructions up to sprinkling on the topping. Cover and refrigerate, with the topping stored in a separate container. Pull it out at least 1 hour before baking to allow it to come to room temperature. Sprinkle the topping over the cauliflower and follow the remaining steps for baking it in the oven.
- To Store: This cauliflower gratin tastes best when it is served immediately. You can save covered leftovers in the refrigerator for up to 3-5 days. Just note it will get soggy and not have the same incredible texture.
- To Freeze: Since the texture will change it is not recommended to freeze. If you do, seal it tightly in a freezer-safe airtight container for up to 3 months.
- To Reheat: Take it out of the fridge 30 minutes ahead of time, then bake at 350°F for 10-20 minutes.
FAQs
Yes you can. Wash and cut the cauliflower, then store it in an airtight container in the refrigerator for up to 3 days.
Mostly. Cauliflower gratin is low in carbs and features cauliflower, which is a healthy vegetable. However the cheese included contains fat which can be considered unhealthy depending on your dietary needs.
You can freeze sealed cauliflower gratin for up to 3 months. Just know that the texture will change.
Watery cauliflower gratin can be caused by a number of reasons. If you boiled the cauliflower instead of roasting you will likely end up with too much moisture. Other causes include if you used too much milk, or if you didn’t wait for the cheese sauce to thicken up.
Expert Tips and Tricks
- Pop it under the broiler. Do this during the last 3-5 minutes of cooking to get a crispy brown crust.
- Similar in size. Cut the cauliflower florets uniformly so they cook up evenly.
- Do not cover. Sealing the dish with foil while baking will trap in all of the excess moisture and make it soggy.
- Splurge for gruyere. This cheese has a unique flavor that pairs well with cauliflower.
- Sprinkle with fresh herbs. Garnish just before serving for an impressive presentation.
More Cauliflower Recipes
Get the most out of this healthy vegetable by trying it in a variety of recipes:
Garlic & Herb Whole Roasted Cauliflower
Roasted Garlic Mashed Cauliflower
Garlic Parmesan Roasted Broccoli and Cauliflower
Cauliflower au Gratin Recipe
Allow me to introduce you to this cheesy Cauliflower au Gratin, your new favorite easy low-carb recipe! Serve this healthy vegetarian casserole for Thanksgiving or any holiday dinner.
Ingredients
- 1 large head cauliflower cut into florets, about 5 cups
- 2 Tbsp. oil olive or avocado
- 1 tsp. salt divided
- ¼ tsp. black pepper
- 2 Tbsp. butter or oil
- 2 cloves garlic crushed
- 2 Tbsp. flour gluten-free 1-to-1 blend
- 1 ½ cups milk regular or cashew milk
- ¾ cup cheese gruyere, asiago, or mixed
- ½ cup Parmesan cheese grated, divided
- ¼ tsp. dried thyme
- ¼ tsp. coriander
- ¼ cup Panko bread crumbs gluten-free, optional
Instructions
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Preheat oven to 425°F.
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Add cauliflower florets to a 13 by 9-inch baking dish along with 2 tablespoons of oil, ½ teaspoon salt, and ¼ teaspoon black pepper.
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Toss to combine and spread cauliflower out in the dish. Bake in preheated oven for 15-20 minutes.
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While cauliflower is baking, add 2 tablespoons of butter and crushed garlic to a large skillet or saucepan. Saute over medium heat for 1 minute.
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Sprinkle flour into the pan and whisk for 1-2 minutes, or until it begins to form a paste.
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Reduce heat to medium-low. Pour in room-temperature milk, ¼ cup at a time, whisking well after each addition. Wait to add the next amount until the sauce has thickened.
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Once all of the milk is added, turn off the heat and mix in gruyere cheese, ¼ cup Parmesan cheese, ½ teaspoon salt, thyme, and coriander.
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Pour sauce over baked cauliflower and toss to combine.
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Mix together remaining Parmesan cheese and breadcrumbs in a small bowl. Sprinkle over cauliflower.
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Reduce oven temperature to 400 °F and return cauliflower dish to oven for 20-25 minutes.
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For an extra crispy topping, broil casserole for 2-3 minutes under a high broil.
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Serve with fresh thyme and enjoy!
Recipe Video
Recipe Notes
- For a keto diet: Leave off the breadcrumbs and you’ll bring the nutritional values to 156 calories, 7 carbs, and 2 grams fiber.
- Feel free to substitute the Gruyere cheese for a white cheese blend, Mozzarella, mild cheddar, or white cheddar.
- To Store: This cauliflower gratin tastes best when it is served immediately. You can save covered leftovers in the refrigerator for up to 3-5 days. Just note it will get soggy and not have the same incredible texture.
- To Freeze: Since the texture will change it is not recommended to freeze. If you do, seal it tightly in a freezer-safe airtight container for up to 3 months.
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