4.75 from 4 votes

Parmesan Cauliflower Casserole

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Are you looking for a twist on classic side dishes? Let Baked Cauliflower Parmesan Casserole take center stage at your dinner table. This creamy, cheesy casserole is a fantastic alternative to traditional potato side dishes and a flavor-packed option that’s sure to impress.

baked cauliflower casserole piled up on a white plate.

Parmesan Cauliflower Casserole Recipe

This cauliflower au gratin is the perfect replacement for your ordinary potato side dish; lower in carbs but bursting with flavor!


  • head of cauliflower, cut into florets
  • unsalted butter
  • all-purpose flour
  • milk
  • heavy whipping cream
  • Grated Parmesan cheese divided
  • garlic powder, ground nutmeg, and Salt and black pepper to taste
  • 1/2 cup Panko breadcrumbs (optional for extra crunch)

Prep before you get started: Before starting this cauliflower gratin casserole, you need to cook your cauliflower. The head of cauliflower needs to be roasted (recommended) or steamed to turn it into a casserole.⭐

How to make Baked Cauliflower Parmesan

Preheat Oven & Prep Cauliflower: Preheat your oven to 375°F (190°C). Steam the cauliflower florets until just tender, about 5-7 minutes, then drain well and set aside.

Make the roux:

  1. In a saucepan, melt butter over medium heat.
  2. Stir in flour to create a smooth paste and cook for 1-2 minutes.
  3. Gradually whisk in milk and heavy cream, ensuring no lumps form.
  4. Bring to a simmer and cook until the sauce thickens.
  • Making roux can be 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.
pouring ingredients into a dish for roux.

Add Cheese and Seasonings

Remove the sauce from heat and stir in 1 cup of Parmesan cheese until melted—season with garlic powder, nutmeg, salt, and pepper.

Combine and bake casserole:

  1. Place the steamed cauliflower in a casserole dish.
  2. Pour the cheese sauce over the cauliflower, ensuring it’s evenly coated.
  3. If using, sprinkle with the remaining 1/2 cup of Parmesan cheese and breadcrumbs.
roux ready to be poured from saucepan.

Bake to Perfection: Bake in the oven for 25–30 minutes or until the top is golden and bubbly.

Serve & enjoy your casserole. Let it cool slightly before serving. Enjoy the creamy, cheesy goodness of your Cauliflower Au Gratin!

cauliflower casserole in baking dish.

Can I use frozen cauliflower with this dish?

Can I make parmesan cauliflower casserole ahead of time?


Assemble the dish up to the baking step, cover, and refrigerate. When you’re ready, bake it as directed, adding a few extra minutes if it’s coming straight from the fridge.

How should I store casserole leftovers?

Store any leftovers in an airtight container in the refrigerator for up to 3 days. Reheat in the oven or microwave until warmed through.

scoop of cauliflower and roux in a metal spoon.

What main dishes pair well with cauliflower au gratin?

Basically, anything that you would pair with a potato side would be an excellent accompaniment to this cauliflower casserole. 

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4.75 from 4 votes

Baked Cauliflower Parmesan Casserole

Prep Time 20 minutes
Cook Time 25 minutes
Total Time 45 minutes
Packed with creamy cauliflower, rich Parmesan, and a flawless roux, Cauliflower Parmesan Casserole is a lower-carb alternative to traditional potato dishes. Elevate it with bacon, sour cream, cheddar, and onions for an extra layer of flavor. Perfect alongside fish or chicken, this veggie casserole boasts a crispy topping of grated cheese and breadcrumbs, ensuring the cauliflower remains the star.


Cauliflower Base:

  • 1 large head of cauliflower – about 2 pounds steamed or roasted and broken into pieces-

Cheese Sauce:

  • 6 tablespoons butter
  • 1/2 cup all-purpose flour
  • 1 1/2 cups heavy whipping cream plus up to 1 additional cup if needed to adjust consistency
  • 1/3 cup grated Parmesan cheese plus more for topping
  • 1 teaspoon salt
  • A pinch of cayenne pepper
  • A pinch of ground nutmeg


  • 2 tablespoons bread crumbs
  • 2 tablespoons shredded Parmesan cheese
  • Chopped fresh parsley optional, for garnish


  • Prepare the Cauliflower: Ensure your cauliflower is cooked by steaming or roasting until tender. Break it into bite-sized pieces. Ensure that the pieces have no extra moisture.
  • Preheat and Prep: Preheat your oven to 425°F (220°C) and grease a 9 x 13 baking dish with non-stick spray.
  • Assemble the Cauliflower Base: Arrange the cooked cauliflower floret pieces in the baking dish. Set aside for the cheese sauce preparation.

Make the Cheese Sauce:

  • Melt butter in a saucepan over low heat. Increase to medium heat, add flour, and whisk until bubbly. Please note that making Roux can be really difficult for some and it can thicken if heated too much and too quickly. 
  • Gradually add heavy whipping cream, whisking until the sauce thickens. Increase to medium heat, add flour, and whisk until bubbly. Off heat, stir in grated Parmesan, salt, cayenne, and nutmeg. Add more heavy cream if too thick.
  • Combine and Top: Cover the cauliflower with cheese sauce, then sprinkle with grated Parmesan and breadcrumbs.
  • Bake to Perfection: Bake casserole for about 25 minutes until golden.
  • Garnish and Serve: Sprinkle with chopped parsley before serving, if desired.


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, you can pre-cook your cauliflower by roasting it for about 10 minutes in the oven at 450 degrees before adding to the baking dish.
What are some great toppings for this dish?
  • Enhance your gratin with toppings like bacon, chives, and sour cream for extra flavor.
  • For a gourmet twist, mix in melted Gruyere cheese, or add seafood like lobster, crab, or shrimp to turn the gratin into a hearty meal.


Serving: 1cups | Calories: 350kcal | Carbohydrates: 18g | Protein: 8g | Fat: 54g | Saturated Fat: 33g | Polyunsaturated Fat: 2g | Monounsaturated Fat: 15g | Trans Fat: 1g | Cholesterol: 176mg | Sodium: 970mg | Potassium: 111mg | Fiber: 1g | Sugar: 1g | Vitamin A: 1928IU | Vitamin C: 1mg | Calcium: 197mg | Iron: 1mg

Nutritional Disclaimer: The nutritional data provided here is auto-calculated and intended for your convenience only. As it’s generated via automation, its accuracy may be compromised. For precise nutritional insight, please compute the values utilizing the actual ingredients in your recipe through your chosen nutrition calculator or application.

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4.75 from 4 votes

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