Recipe Overview
Why you’ll love it: Cauliflower and potato casserole topped with creamy cheese sauce is a comfort food side dish. Whether you make it for a holiday or a weeknight dinner, it’s guaranteed to disappear fast!
How long it takes: 1 hour, 25 minutes
Equipment you’ll need: saucepan, 9 x 13-inch baking dish
Servings: 8
The Perfect Marriage of Two Recipes
Consider cauliflower and potato casserole as a happy medium between cheesy potatoes and plain roasted cauliflower. Combining the two is the best of both worlds!
What I really love about this recipe—well, aside from that glorious cheese sauce—is that the cauliflower and potatoes are roasted instead of boiled or steamed, which is more typical in a casserole like this. Roasting them adds so much more flavor. The cauliflower gets caramelized and the potatoes get ever-so-slightly crisp on the edges.
What makes it special:
- Meal-prep friendly: Assemble in advance or roast the veggies ahead to save time. Great for holidays, too!
- Cheesy comfort without the heaviness: Cauliflower and potato casserole is a little bit lighter without sacrificing the flavor or richness you want in a casserole.
- Easy to prep: While the potatoes and cauliflower roast, you can make the cheese sauce. Once the potatoes are ready, pour the sauce over the veggies (right in the same dish), add the buttery bread crumb topping, and bake the two together until the sauce is thickened and bubbly.
How to Make Cauliflower and Potato Casserole
Prepare. Preheat your oven to 375°F and lightly grease a rectangular 9 x 13-inch casserole dish.
Roast the veggies. After you wash and dry the cauliflower florets, peel and dice the potatoes. Toss the cauliflower and potatoes with olive oil, salt, and pepper, making sure they’re evenly coated. I usually do that right in the baking dish. Roast for 25 minutes.
Make the cheese sauce. Melt the butter in a saucepan set over medium heat. Once it’s melted, whisk in the flour and the seasonings. Let the flour/butter mixture (roux) cook until it’s golden brown (just a minute or so), then slowly whisk in the milk. Cook until the sauce comes to a boil and thickens.
Reduce the heat to low. Add the cheddar cheese in handfuls—stir to incorporate, then add the next handful—and stir in the Parmesan cheese and seasonings. If you add the cheese all at once, it tends to clump and doesn’t melt as smoothly.
Recipe Tip
Pre-shredded cheese has additives that prevent it from melting smoothly, resulting in a grainy sauce. Shredding your own cheese is your best bet for smooth, creamy results.
Assemble. Pour the cheese sauce over the roasted veggies and stir to coat. To make the topping, melt the butter in a small microwave-safe bowl, and stir in the breadcrumbs and Parmesan cheese. Sprinkle the mixture evenly over the casserole.
Bake. Place the pan back into the oven and bake for 30 to 35 minutes, or until the topping is golden brown and the cheese sauce is bubbly. Let the casserole cool for 10 minutes, then serve.
Recipe Variations
- Make it a meal. You can add diced cooked ham (either leftovers or cook up a ham steak) to make this casserole a complete meal. Leftover cooked chicken or cooked ground beef are okay, too.
- Add bacon. Cooked bacon, either stirred into the casserole or crumbled into the topping, adds fantastic smoky flavor!
- Switch up the cheese. Try gouda, Swiss, smoked cheddar, pepper jack, or other varieties with good flavor and meltability.
- Try a different topping. If you prefer, make the topping with crushed potato chips or Ritz crackers, or sprinkle on additional shredded cheese. You can also skip the topping if you prefer.
Serving Suggestions
- Chicken. Serve this casserole with roasted bone-in chicken breasts or air fryer chicken drumsticks for a weeknight dinner.
- Pork. The creamy, cheesy casserole pairs well with baked breaded pork chops or breaded air fryer pork chops. Try it with bacon wrapped pork tenderloin for a special dinner.
- Salad. A fresh salad is a good balance to a rich, cheesy dish like this cauliflower and potato casserole! Try my wedge salad for something a little different.
- Vegetable casseroles. If you’re serving this for a holiday, it would work with other classic veggie sides like homemade green bean casserole and zucchini casserole.
Refrigerate: Store any leftover cauliflower and potato casserole in an airtight container in the refrigerator for up to 4 days. If you have a lot left, you can simply wrap it in the baking dish. Potatoes tend not to freeze and thaw well (they get mealy!), so I don’t recommend freezing your leftovers.
Reheat: You can warm leftovers in the casserole dish; let it sit at room temperature while you preheat the oven to 350ºF, then bake until the casserole is warmed through. (The exact amount of time will depend on the amount of leftovers in the dish.) You can also heat individual portions in the microwave.
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Ingredients
For Roasted Vegetables:
- 1 head cauliflower, cut into small florets (about 8 cups cauliflower)
- 1 ½ pounds russet potatoes, peeled & diced into ½-inch chunks (about 4 cups)
- 2 tablespoons olive oil
- 1 teaspoon kosher salt
- ¼ teaspoon coarse ground black pepper
For Cheese Sauce:
- 3 tablespoons butter
- 3 tablespoons all-purpose flour
- 1 teaspoon garlic powder
- ½ teaspoon onion powder
- ½ teaspoon ground mustard (optional but recommended)
- ¼ teaspoon kosher salt
- ¼ teaspoon coarse ground black pepper
- 2 cups milk (I recommend whole milk or 2%)
- 1 cup shredded sharp cheddar cheese (see notes)
- ½ cup grated Parmesan cheese
For Topping:
- ½ cup panko breadcrumbs
- 2 tablespoons grated Parmesan cheese
- 1 tablespoon butter, melted
Instructions
- Preheat oven to 375°F. Lightly grease a 9 x 13-inch baking dish.
- In the prepared pan, toss cauliflower and potatoes in olive oil, salt, and pepper. Roast for 25 minutes.1 head cauliflower, cut into small florets, 1 ½ pounds russet potatoes, peeled & diced into ½-inch chunks, 2 tablespoons olive oil, 1 teaspoon kosher salt, ¼ teaspoon coarse ground black pepper
- Meanwhile, in a saucepan, melt butter over medium heat. Whisk in flour, garlic powder, onion powder, ground mustard, salt, and pepper; cook for 1 minute to form a roux. Slowly whisk in milk, stirring constantly until the sauce comes to a boil and is slightly thickened (5 to 6 minutes).3 tablespoons butter, 3 tablespoons all-purpose flour, 1 teaspoon garlic powder, ½ teaspoon onion powder, ½ teaspoon ground mustard, ¼ teaspoon kosher salt, 2 cups milk, ¼ teaspoon coarse ground black pepper
- Reduce heat to low, and gradually stir in the cheddar cheese and Parmesan (don't dump it in the sauce all at the same time). Stir until the cheese is melted and the sauce is smooth. Remove from heat.1 cup shredded sharp cheddar cheese, ½ cup grated Parmesan cheese
- Pour cheese sauce over the roasted cauliflower and potatoes and gently mix to coat.
- To make the topping, in a small microwave-safe bowl, melt 1 tablespoon butter. Stir in the breadcrumbs and 2 tablespoons Parmesan cheese. Sprinkle the mixture evenly over the casserole.½ cup panko breadcrumbs, 2 tablespoons grated Parmesan cheese, 1 tablespoon butter, melted
- Bake for 30 to 35 minutes, or until golden and bubbly. Let rest 10 minutes before serving.
Notes
- Cauliflower: After you rinse the cauliflower, make sure to dry it fairly well. The florets can hold quite a bit of water and could make your casserole too juicy. A quick spin in your salad spinner does the job.
- Potatoes: We recommend russet potatoes, but Yukon gold potatoes also work well. Although you can skip peeling the potatoes (especially the Yukon gold potatoes), we found that we preferred the potatoes peeled in this casserole.
- Pro tip: For best results, shred your own cheddar cheese instead of using pre-shredded. Pre-shredded cheese has an anti-clumping additive and doesn’t melt as smoothly. You can also substitute another type of cheese, if you prefer.
- Topping: We use panko breadcrumbs which have a much coarser texture than regular breadcrumbs, so it gets nice and crispy. Homemade breadcrumbs would also work. If you prefer, you can skip the topping or try an alternative topping, such as crushed potato chips, cracker crumbs, additional shredded cheese, and so on.
- Make it a meal: To add protein to this veggie dish, add diced cooked ham when you stir in the cheese sauce. You could also use cooked chicken, albacore tuna, or even browned ground beef.
- Recipe retested and revised 8/2025.
Video
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
Did You Make This?Share a comment and rating below! I love hearing what you think!
Will this work with non dairy cheese?
I haven’t tested it that way, so I can’t say for sure. I think it would work, but it might be a little less creamy. Let me know if you give it a try!
Did this recipe change? It has been a go to for us for years because it is so good and I swear I’ve never made a cheese sauce or roasted the veggies.
I sent you an email. :) Yes it’s been updated, but we save the old one too, so I sent that to you!
This cauliflower, potato, and cheddar bake is perfect
So glad you liked it!
Going to make this for Thanksgiving!
I hope you love it!