Cheesy Cauliflower Gratin — Cauliflower florets are coated in a creamy cheese sauce and sprinkled with a crispy panko breadcrumb topping before being baked to golden, bubbly perfection! This is an EASY yet ELEGANT side dish that’s perfect for busy weeknights and holiday meals alike including Thanksgiving, Christmas, or New Year’s Eve!
Table of Contents
Easy Cauliflower au Gratin Recipe
Cauliflower gratin has everything I want in a great side dish — it’s quick to assemble, can be made with pre-chopped bags of cauliflower florets for even easier prep, and it’s packed with two types of cheese.
It’s a hearty casserole disguised as an elegant side dish. I mean, it’s essentially baked cauliflower with a creamy cheese sauce that’s presented in a pretty way. Not that I’m complaining whatsoever!
Any recipe that gets my whole family to eat their vegetables and takes just 15 minutes of active prep time to whip up is wonderful by me. It’s a great weeknight dinner side especially when the weather turns chillier. Roasted vegetables of any kind are always a favorite.
But it’s also a wonderful side dish to add to your Thanksgiving, Christmas, or Easter dinner. Despite the cheese sauce, it’s not as heavy-tasting as green bean casserole or sweet potato casserole, but it’s still incredibly rich. This easy cauliflower au gratin holds its own next to classic holiday entrees like glazed ham,roast turkey, glazed pork loin roast, or slow cooker turkey breast.
As written, the recipe comfortably feeds six people as a side dish, but you’re welcome to double the recipe if you’re expecting additional company this holiday season.
What Is Cauliflower au Gratin?
Cauliflower gratin is essentially a baked cauliflower cheese casserole that’s made with fresh cauliflower florets tossed in a creamy homemade cheesy sauce and covered with a crispy panko breadcrumb topping.
The term “au gratin” is French for “with a crust”.
Generally speaking, any dish with the label “au gratin” attached to it means it’s been topped with breadcrumbs and / or cheese and then baked.
Because I can’t resist cheese, and because I like to think of this as more of a special occasion side dish, I topped this easy cauliflower gratin recipe with both Gruyere AND Parmesan cheese.
Cauliflower Gratin Ingredients
Don’t let the “au gratin” title fool you into thinking this cauliflower cheese bake is in any way complicated or requires special ingredients. It’s actually the complete opposite!
You’ll need the following easy-to-find ingredients to make this recipe:
- Cauliflower florets
- Olive oil
- Seasoning salt
- Butter
- All-purpose flour
- Milk (whole milk is best)
- Salt
- Fresh thyme
- Grated nutmeg
- Gruyere cheese (or Swiss cheese)
- Panko bread crumbs
- Grated Parmesan cheese
Note: Scroll down to the recipe card section of the post for the ingredients with amounts included and for more complete directions.
How to Make The Best Cauliflower Gratin
This is a straightforward recipe but there are few different steps to it. The cauliflower has to be roasted before being coated in the homemade creamy cheese sauce and then baked again together. Because if you don’t roast the cauliflower, the finished casserole could be either very watery once baked and/or the cauliflower will still be too crunchy or raw.
Here’s an overview of how this recipe comes together:
Step 1: On a baking sheet, toss the cauliflower florets with olive oil and season with seasoning salt. Bake at 425ºF for about 20 minutes.
Seasoning Salt
Seasoning salt (or seasoned salt, same thing) is a mix of salt (not shocking), pepper, and other seasonings.
I use a solid 2 teaspoons of seasoning salt when I am seasoning the raw cauliflower before roasting it on the sheet pan. Cauliflower is a pretty bland vegetable and needs to be properly seasoned so it has some actual flavor. Plus, you are roasting a head of it. That’s a lot! So 2 teaspoons is by no means ‘too much’.
If you don’t have seasoning salt on hand, I would use 1-2 teaspoons kosher salt plus 1/2 to 1 teaspoon freshly ground black pepper. Of course, always season to your tastes, not mine! There are other spices in seasoning salt like paprika and onion, but your roasted cauliflower will still be fine without it and you can just use good ole S&P.
Step 2: While the cauliflower bakes, make the cheese sauce. You’ll first melt the butter in a saucepan, then stir in the flour. Whisk in the milk, salt, thyme, and optional nutmeg. This is your roux.
Step 3: Keep cooking the roux, stirring continually, until thickened. Then, stir in the grated cheeses and cook just until they’re totally melted.
Step 4: Add the roasted cauliflower pan to a 2-quart baking dish.
Step 5: Pour the warm cheese sauce over top.
Step 6: Combine the panko breadcrumbs with additional Parmesan cheese and sprinkle evenly over the cauliflower.
Step 7: Bake the au gratin cauliflower casserole at 375ºF until slightly golden and the edges are bubbling.
Cheesy Cauliflower Gratin Recipe FAQs
If you didn’t roast the cauliflower prior to topping it with cheese sauce, it’s going to make the finished cauliflower gratin casserole watery. Cauliflower contains a lot of moisture, and roasting it removes most of the excess moisture.
Plus roasting provides that lovely roasted vegetable flavor which makes even ‘plain’ vegetables like cauliflower have more flavor and pizazz.
Also, the cauliflower in the gratin would be crunchy and half raw if you don’t roast it first, so don’t skip this step! Normally I am all about some crisp-tender veggies but this is a time where softer is better.
Any dish labeled as “au gratin” typically has a cheese and / or breadcrumb topping and is baked in a casserole dish.
If your cheese sauce curdled, you likely got it too hot. Although it probably didn’t start with the cheese; it probably started with the roux + milk. Make sure when you add the milk that you really watch the heat and don’t let it come up to any type of fast boil – just a simmer.
Then, after you add the two types of shredded cheese, also watch the heat. You need to cook over medium to medium-high heat to prevent it from curdling. And continue cooking just until the cheeses have melted and then immediately remove from the heat to prevent curdling.
The first thing to remember is to stir it constantly to prevent lumps. I like to use a wire whisk for this job. You should also remember to cook the cheese sauce at medium to medium-high heat, otherwise it will curdle and form lumps.
But the MOST IMPORTANT thing to do is to shred your own cheeses using a box grater. Pre-shredded cheese sold in a bag is coated in starch or another anti-caking agent which can make cheese sauces grainy or gloopy in texture. Buy an actual block of cheese and shred it yourself for the smoothest, creamiest cheese sauce for your cauliflower gratin recipe.
While you can sometimes find Parmesan already shredded in bags, it’s not super common. And I have never seen Gruyere sold like that so you need to shred it anyway. May as well just shred two blocks. Literally this is a 1 minute job per block, tops. 
I use 1 cup Gruyere cheese and 1/2 cup Parmesan in total for this recipe. I do recommend those two cheeses to preserve the elegant flavor and nice meltability they lend.
Gruyere is pricey, I know. However, it’s worth the splurge. Use the rest of it in either French Onion Pork Chops or French Onion Soup! The only real acceptable substitute is Swiss cheese.
For the Parmesan, it’s really ‘go Parm, or go home’ here! I can’t think of any acceptable substitution.
I use whole milk in this recipe. You can probably get away with 2% if you’re trying to shave off some fat and calories, although it won’t be quite as rich tasting. However, don’t use a lighter milk that that (no 1% or skim).
If you’re wanting to go all out, half-and-half will definitely make for a super rich and creamy cheese sauce. However, more is not better. I actually would not use heavy cream here as it’s too thick an rich and the sauce may end up being too thick or heavy.
Panko breadcrumbs are sometimes known as Japanese bread crumbs, and yes, you have to use them. They will lend the most wonderful little bit of crispy crunch to this easy holiday or elevated weekday side dish recipe.
Do NOT use regular Italian-style breadcrumbs. They are soft, mushy, and will not do the texture of the soft (and almost mushy) cauliflower any favors so avoid.
Wondering what to do with extra panko breadcrumbs? I have 20+ recipes using panko breadcrumbs right here. 
This is one casserole that’s best enjoyed right away. You might be able to roast the cauliflower in advance, then make the cheese sauce day-of but I’m not 100% convinced that will be delicious and actually sounds like more work than it’s worth.
So, I suggest making the recipe as written on the day you plan on serving the cheesy cauliflower casserole. It will hold decently well at room temp for an hour or two so if you’re setting this out on a Thanksgiving buffet table, it’s fine if it’s not immediately consumed piping hot from the oven.
You can use one large head of cauliflower OR two bags of cauliflower florets that have been pre-chopped and washed (although some bags say you can skip the washing and I admit I don’t bother if I have just purchased a convenience product).
Bagged cauliflower is more expensive, by a long shot, ounce for ounce. Although still not “expensive”, you do get much more value if you chop your own. If you are using bagged, make sure that the sizes of the pieces are pretty uniform. I have found within bags of either broccoli or cauliflower, there are always a few very big pieces that you should take a paring knife to and pare down to actual bite-sized.
Make sure to use fresh cauliflower because frozen will not work. 
No, I do not recommend using frozen cauliflower to make cauliflower au gratin. Frozen cauliflower releases extra moisture in the oven and would likely end up being too mushy to suit the creamy cheese sauce. 
Storage Instructions
Store leftover au gratin cauliflower in the fridge for up to five days. Cover the pan with plastic wrap or transfer the leftovers to an airtight container to keep it fresh. I reheat leftovers in the microwave, but you can also warm servings in a 350ºF oven in about 10 minutes.
I don’t think the casserole would freeze well since it’s made with a cheese sauce and then you will have to contend with the potential mushy nature of frozen-and-thawed cauliflower. Nope. As such, you need to enjoy it within about five days of baking it.
What to Serve with Cauliflower Gratin
Au gratin cauliflower works well with just about any grilled or baked protein and is perfect for either weeknight dinners or holiday get-togethers!
Serve the cheesy baked cauliflower casserole with one of the following entrees:
- Orange Pineapple Ham
- Glazed Pork Loin Roast
- Slow Cooker Pork Tenderloin
- Classic Roasted Turkey
- Slow Cooker Turkey Breast
- Turkey Tetrazzini
- French Onion Pork Chops
- Baked BBQ Beef Short Ribs
- Melt in Your Mouth Chicken
- Perfect Baked Chicken Breasts
- Baked Lemon Garlic Butter Salmon
- Air Fryer Meatloaf
- Maple Glazed Pork Chops
Pin This Recipe
Enjoy AverieCooks.com Without Ads! 🆕
Go Ad Free
Cauliflower Gratin
Ingredients
- two 12-ounce bags cauliflower florets OR 1 large head of cauliflower, trimmed and cut into florets
- 2 tablespoons olive oil
- 1 to 2 teaspoons seasoning salt, or as desired
- 2 tablespoons unsalted butter
- 2 tablespoons all-purpose flour
- 1 ½ cups whole milk, 2% or half-and-half may be substituted
- ½ teaspoon salt, or to taste
- ½ teaspoon fresh thyme
- ¼ teaspoon ground nutmeg, optional* (See Notes)
- 1 cup Gruyere cheese, grated
- ½ cup panko bread crumbs, do not use regular bread crumbs
- ½ cup shredded parmesan cheese, divided
- Fresh parsley or fresh thyme, optional for garnishing
Instructions
- Preheat oven to 425F. If you have a convection oven, now is a great time to use it.
- If desired for easier cleanup, line a baking sheet with foil. Spray the baking sheet (or the foil on top of it) with cooking spray and evenly scatter the cauliflower florets. Tip – Make sure they are all actually bite-sized which is practical for both eating them and so that they all cook evenly.
- Roasting Cauliflower – Evenly drizzle with olive oil, evenly sprinkle with seasoning salt, and toss with your hands to combine and coat evenly. Tips – I use 2 teaspoons seasoning salt because cauliflower needs a lot of help in the salt department and you are flavoring a very large amount of a bland vegetable, but of course, season to taste. If you don't keep seasoning salt on hand, then I would use 1 to 2 teaspoons kosher salt and 1 teaspoon freshly ground black pepper, or to taste.
- Roast for about 20 minutes, or until golden browned around the tips and edges, and tender. Depending on their size and your oven, they may be done 5 minutes early, or 5 minutes later, so keep a watchful eye and check on them early. If desired, you can flip and toss them once midway through roasting for even cooking. Tip – While the cauliflower roasts, move onto the next steps so the sauce is ready when the cauliflower is done.
- Cheese Sauce – To a medium saucepan, add the butter and heat over medium heat to melt, about 1 minute; stir constantly.
- Once melted, sprinkle the flour over the butter and cook for 1 minute, or until sand colored; whisk constantly. This is called making a roux. Tip – Do not shortchange this step because the finished dish will both taste awful from the raw flour and the cheese sauce will be thin and runny.
- Slowly add the milk, salt, thyme, optional nutmeg, and cook for about 3 minutes, or until thickened; whisk constantly to avoid lumps and ensure even thickening.
- Add the Gruyere cheese, half the Parmesan, and heat until the cheese melts; whisk constantly. Take off the heat and set aside once melted and combined.
- Assembly – To a 1.7-quart baking dish (or similar sized baking dish) that's sprayed with cooking spray, add the cauliflower and smooth it evenly.
- Evenly pour the cheese sauce over the top.
- In a small bowl, combine the the panko breadcrumbs, remaining Parmesan cheese, stir to combine. And evenly sprinkle this mixture over the top of the cheese sauce.
- Baking – Reduce the oven heat to 375F (if you are using convection, reduce the heat to 375F convection) and bake for about 20 minutes, or until the top is lightly golden browned or as desired.
- Serving- Optionally garnish with fresh herbs and serve.
- Storage – Extra gratin will keep airtight in the fridge for 5 days. Reheat gently in the microwave as desired. I don't recommend freezing this dish due to the cheese sauce and the texture of the cauliflower will also change during the freezing/thawing process.
Notes
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
©averiecooks.com. Content and photographs are copyright protected. Sharing of this recipe is both encouraged and appreciated. Copying and/or pasting full recipes to any social media is strictly prohibited.
More Easy Cauliflower Recipes:
Roasted Curried Cauliflower and Chickpea Salad – An EASY, healthy, lettuce-less salad with roasted curried cauliflower and chickpeas as the STARS!! Topped with raisins, pistachios, cilantro, and a DELISH tangy Greek yogurt dressing!
Roasted Cauliflower with Parmesan Dipping Sauce — Even people who say they don’t like cauliflower will love this version! Oven roasted cauliflower is easy to prepare, and I’ve given detailed instructions on bake times and oven temperatures.
Sweet Chili Sauce Chicken and Vegetables — EASY, ready in 15 minutes, made on ONE sheet pan, and perfect for busy weeknights!! Accidentally healthy yet packed with the perfect flavor balance – a little bit sweet with a little bit of heat!!
Kung Pao Cauliflower — An EASY recipe that has salty-sweet-tangy-spicy flavors all in one!! Don’t call for takeout when you can make this HEALTHY dish at home in 20 minutes! You won’t believe how AUTHENTIC it tastes!!
Thai Chicken Cauliflower Curry — An EASY, one-skillet curry that’s ready in 20 minutes and tastes BETTER than a restaurant!! The Thai-inspired coconut milk broth makes this healthy comfort food taste AMAZING!!
Skinny Chicken and Cauliflower Rice Stir-Fry — Even people who don’t like cauliflower will be amazed at how authentic and DELICIOUS this SKINNY version of chicken fried rice tastes!! Easy, ready in 15 minutes, and so much HEALTHIER than calling for takeout!!
10-Minute Sheet Pan Dijon Salmon and Vegetables — Juicy salmon and crisp-tender vegetables coated with a buttery Dijon honey lemon sauce for an explosion of FLAVOR!! So EASY and ready so FAST!!
Cauliflower Tinga Tacos with Avocado Crema — Roasted cauliflower is drenched in a smoky, perfectly spicy chipotle sauce, then folded into corn tortillas, cheese is added, and baked to crispy perfection! A bright avocado crema sauce is the finishing touch! Naturally gluten-free vegetarian food never tasted so AMAZING! You’ll never miss the meat in these healthy tacos!
15-Minute Cheesy Chicken Veggie Pasta — EASY and ready in minutes!! The cheesy pasta is COMFORT food while all the veggies add a HEALTHIER twist! Family-friendly and perfect for busy weeknights!!
Browned Butter Cauliflower with Parmesan Fettuccine – Everything is better with browned butter and it can make humble cauliflower and average noodles taste like a million bucks.
