Creamy, cheesy, and finished with a crisp golden crust, mashed cauliflower and cheese casserole is a comforting side that even cauliflower skeptics will enjoy.
As a child I avoided cauliflower, but over time I learned to appreciate its mild flavor and versatility—now I’ll even eat it raw. Properly prepared, mashed cauliflower can approach the texture and comfort of mashed potatoes while remaining lighter.
If you love creamy sides but want something less heavy than traditional mashed potatoes, this Mashed Cauliflower and Cheese Casserole is a delicious alternative that works for weeknights and holiday feasts alike. It’s rich, cheesy, and topped with buttery Panko for a satisfying crunch.
“Such a great treat! I enjoyed making it and my family loved it!”
-Jeannine
Recipe at a glance
- Creamy mashed cauliflower baked with melted cheese and a crunchy buttery breadcrumb topping.
- All the comfort of cheesy potatoes, but lighter and lower in carbs.
- Can be assembled a day ahead and baked before serving.
- Perfect for both busy weeknights and holiday tables.
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Use the recipe card below for full ingredient amounts, instructions, and nutritional information.
Ingredients you will need
This cauliflower casserole is flavorful yet made from straightforward ingredients that keep it lighter than a potato casserole. Key ingredients include:
See the recipe card below for exact quantities.
- Cauliflower – Steam and mash for a creamy, lower-carb base.
- Parmesan – Adds salty, nutty depth and helps bind the mash.
- Colby-Monterey Jack – Melts smoothly for gooey, mild cheesiness.
- Butter – Brings richness to the mash and the breadcrumb topping.
- Garlic powder – For subtle savory flavor.
- Montreal steak seasoning – A blend that adds a robust, peppery note.
- Thyme – A light herbal touch that complements the cheeses.
- Panko breadcrumbs – Provide a crisp, airy topping when mixed with butter.
- Salt and pepper – Essential to balance and enhance the flavors.
Substitutions and variations
- Cheese swaps: Use sharp cheddar, Gruyère, or mozzarella for different flavor profiles.
- Low-dairy or vegan: Replace butter with olive oil and use dairy-free cheeses.
- Add protein: Stir in cooked bacon, diced ham, or shredded chicken for a heartier dish.
- More flavor: Use roasted garlic instead of garlic powder or finish with fresh herbs like parsley or chives.
- Extra veggies: Fold in cooked spinach, caramelized onions, or roasted broccoli for color and nutrition.
- Make it spicy: Add crushed red pepper flakes or use pepper jack cheese.
- Keto topping: Substitute crushed pork rinds or almond flour for Panko to keep it low-carb.
How to make mashed cauliflower and cheese casserole
Step 1: Fill a large pot about one-quarter full of water and bring it to a boil. Place cauliflower florets in a steamer basket over the pot, cover, reduce heat to medium, and steam until very tender, about 20 minutes.
Step 2: Transfer the steamed cauliflower to a large bowl and mash with a potato masher, ricer, or run through a food mill for an extra-smooth, almost potato-like texture.
Step 3: Stir in Parmesan, shredded Colby-Monterey Jack, butter, garlic powder, Montreal steak seasoning, thyme, salt, and pepper while the cauliflower is still warm so everything melts together smoothly. Mix Panko breadcrumbs with melted butter and season to taste.
Step 4: Preheat the oven to 350°F. Spread the mashed cauliflower in a greased 8×8-inch casserole dish or a 10-inch cast iron skillet. Evenly distribute the breadcrumb mixture across the top.
Step 5: Bake uncovered for 40–50 minutes, until the topping is golden and the cheeses are bubbly. Let rest briefly before serving.
Pro tip: Stir in a handful of sharp cheddar or sprinkle crispy bacon on top before baking for extra flavor.
Serving suggestions
This casserole pairs beautifully with roasted or grilled mains like roasted chicken, steak, or salmon. It also fits seamlessly into holiday menus—rich, comforting, and likely to become a favorite side.
Storage, freezing, and reheating
Storage: Cool completely, then transfer leftovers to an airtight container and refrigerate for up to 4 days. If baked in cast iron, transfer leftovers out of the skillet before storing to prevent rust.
Freezing: Assemble the casserole but don’t bake it. Wrap tightly in plastic and foil and freeze up to 3 months. Thaw overnight in the refrigerator, then bake as directed. Fully cooled baked leftovers can also be frozen.
Reheating: Reheat covered in a 350°F oven until warmed through, 20–25 minutes. Remove the cover for the last few minutes to crisp the topping. For single servings, microwave until hot, then broil briefly to restore crunch.
Cauliflower and Cheese Casserole FAQs
Yes. Steam or boil frozen cauliflower until very tender and drain well before mashing to remove excess water.
Yes. Use about 6–7 cups of riced cauliflower to replace one large head. Cook according to the package directions, drain any extra moisture, and continue with the recipe.
Absolutely. Assemble the casserole a day ahead, refrigerate covered, and bake when ready to serve.
Stir in a splash of heavy cream or a spoonful of cream cheese, or blend the cooked cauliflower in a food processor for a velvety texture.
Yes. For a lower-carb option, omit the Panko or replace it with crushed pork rinds or almond flour for a crispy, gluten-free alternative.
Yes. Use a pot-in-pot method with the rack and a cup of water. Place a heatproof bowl with cauliflower on the rack, steam or pressure cook until tender, and allow a brief natural release.
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Yellow Squash Casserole
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Mashed Cauliflower and Cheese Casserole
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Ingredients
For the cauliflower:
- 1 large head of cauliflower broken into florets
- ¾ cup shredded Parmesan cheese
- ½ cup shredded Colby-Monterey Jack cheese
- 3 tablespoons unsalted butter cubed
- ½ teaspoon garlic powder
- ¼ teaspoon Montreal steak seasoning
- ¼ teaspoon dried thyme
- Salt and pepper to taste
For the breadcrumb topping:
- 1 cup Panko bread crumbs
- ¼ cup unsalted butter melted
Instructions
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Fill a large stockpot about ¼ full of water and bring to a boil.
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Place cauliflower florets in a steamer basket over the pot, cover, reduce heat to medium, and steam until very tender, about 20 minutes.
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Transfer the cauliflower to a large bowl and mash with a potato masher, ricer, or process through a food mill until smooth.
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Stir in cheeses, butter, garlic powder, thyme, Montreal steak seasoning, salt, and pepper. Spread the mixture in a greased 8×8-inch casserole dish.
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Preheat the oven to 350°F.
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Combine breadcrumbs and melted butter, season with salt and pepper, and spread in an even layer over the cauliflower.
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Bake uncovered for 40–50 minutes until the cheese is melted and the topping is golden brown.
Notes
Drain excess moisture: If the cauliflower is watery after cooking, pat it dry or let it drain in a colander before mashing to prevent a runny casserole.
Mash to your preference: Use a food processor or immersion blender for a silky finish, or a potato masher for a chunkier texture.
Mix while warm: Adding butter and cheese while the cauliflower is hot helps everything melt together smoothly.
Make ahead: Assemble the casserole up to a day in advance, refrigerate covered, and bake when ready.
Customize the topping: Stir grated Parmesan or chopped nuts into the breadcrumbs for extra crunch, or cover the casserole for the first 30 minutes if you prefer a softer top.