Cauliflower Au Gratin

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If you like scalloped potatoes or potatoes au gratin, then prepare to meet your new favorite side dish recipe: Cauliflower Au Gratin. This easy vegetable casserole features a creamy garlic Alfredo sauce that will convince even picky eaters to enjoy eating vegetables.

Cauliflower gratin in a casserole dish.


 

From steaks to gnocchi and pizza crusts to rice, there’s little cauliflower florets can’t do.

While potatoes often get all the glory when we’re talking about gratins (don’t miss my best Scalloped Potatoes recipe), this dish proves that tender, mild cauliflower can stand in for the spuds in this ultimate comfort food casserole too.

Once coated in a creamy garlic Alfredo sauce that has flavor so delicious I could literally drink it by the spoonful, then topped with crispy bread crumbs and baked to a brilliant golden-brown, this side dish recipe is bound to become a favorite at your dinner table.

Recipe ingredients

Labeled ingredients for cauliflower gratin.

At a Glance: Here is a quick snapshot of what ingredients are in this recipe.
Please see the recipe card below for specific quantities.

Ingredient notes

  • Cauliflower: Seek out a head of this cruciferous vegetable that’s about 3 pounds and in any color. (I often spot white, purple, and orange at my supermarket.) Use a knife to slice the cauliflower into bite-sized florets. Reserve the stems for Vegetable Stock, Cauliflower Rice, or Buffalo Cauliflower Dip.
  • Cheese: Ideally, start with a block of Parmesan and use a box grater or pulse in a food processor to shred it yourself. Pre-shredded cheese can contain ingredients that prevent the cheese from melting as smoothly as it does fresh from the brick. If you have a brand of shredded cheese that you enjoy, go ahead and use it of course.
  • Nutmeg: Just a pinch of this spice cabinet staple lends an earthy, nutty sweetness. I rely on nutmeg as my secret ingredient in many white sauce recipes to add unexpected complexity.
  • Bread crumbs: Start with ½ cup from a carton of store-bought bread crumbs, or to make your own bread crumbs, to a food processor, add 2 pieces of torn bread. Pulse 3 or 4 times, then let the machine run for a few seconds for coarse crumbs or a little longer for fine crumbs.

Step-by-step instructions

  1. Adjust an oven rack to the middle position and preheat to 450 degrees. Coat a 2 1/2-quart casserole dish with nonstick spray. In a Dutch oven or large pot, bring 4 quarts water and 1 tablespoon salt to a boil. Add cauliflower and cook until tender, 3 to 4 minutes. Do not overcook. Transfer to a colander and rinse with cold water to stop the cooking. Drain well.
Cauliflower in a colander.
  1. Meanwhile, melt 2 tbsp butter in a large skillet or medium saucepan over medium heat until the foaming subsides. Stir in shallots and cook until softened, about 2 minutes. Stir in garlic and thyme until fragrant, about 30 seconds.
Garlic, oil and spices in a black skillet.
  1. Stir in all-purpose flour and cook until lightly browned, about 1 minute. Whisk in cream, Parmesan cheese, nutmeg, and salt and pepper to taste (I like 1 teaspoon of salt and ½ teaspoon pepper). Bring to a boil; reduce heat and simmer until thickened, 1 to 2 minutes.
Cauliflower gratin in a black skillet.
  1. Off the heat, add cauliflower and toss in the cheese sauce to coat. Pour into the prepared baking dish and top with panko breadcrumbs.
Cauliflower gratin in a casserole dish before being baked.
  1. Bake until hot and bubbly, about 12 to 15 minutes. Serve immediately.
Cauliflower gratin in a casserole dish.

Recipe tips and variations

  • Yield: This Cauliflower Gratin recipe makes six 1-cup servings; ideal to enjoy as a hearty comfort food side dish.
  • Storage: Store leftovers in an airtight container in the fridge for up to 4 days.
  • Make ahead: Prepare the Cauliflower Gratin through Step 4, then pour the mixture into a casserole dish, cover, and refrigerate for up to 2 days. When ready to bake, top with bread crumbs, and continue with Step 5. 
  • Make this the meal: Tiptoe this delicious side dish into main course territory by layering thinly sliced ham or shredded rotisserie chicken between the potatoes or crumble cooked bacon over the top of the casserole.
  • Upgrade your garnish: Why stop at bread crumbs alone? Before serving, sprinkle on some chopped fresh herbs such as thyme, rosemary, fresh parsley, sage, or chives. Feel free to top with more cheese, like cheddar cheese, sharp cheddar cheese, or gruyere cheese.
Dr. Pepper ham and vegetables on a plate.
Cauliflower Gratin with Dr. Pepper Ham and Roasted Zucchini.

Frequently Asked Questions

What does “gratin” mean?

Gratin is a cooking technique that involves topping a mixture of ingredients with a crust (which often features cheese, breadcrumbs, and egg or butter) inside a shallow baking dish. As this cooks, a brown and crunchy crust forms on top and the inside of the gratin recipe gets bubbly and warm. By this definition, Baked Mac and Cheese to Chicken Tetrazzini also qualify, but creamy vegetables and tubers are often the stars in gratin casserole recipes.

Can I make slow-cooker Cauliflower Gratin instead of baking it?

If you’re short on oven space but not on time, sure! Just prepare the filling, then build the dish following the same instructions inside a lined slow cooker pot. Cover and cook on LOW for 8 to 10 hours. The bread crumbs won’t get quite as toasty or crispy on top, but the cozy casserole recipe will still taste fabulous.

More cozy sides

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Cauliflower gratin in a casserole dish.

Cauliflower Au Gratin

If you like scalloped potatoes or potatoes au gratin, then prepare to meet your new favorite side dish recipe: Cauliflower Au Gratin. This easy vegetable casserole features a creamy garlic Alfredo sauce that will convince even picky eaters to enjoy eating vegetables.
Prep Time 5 minutes
Cook Time 35 minutes
Total Time 40 minutes
Servings 6 servings (1 cup each)
Course Side Dish
Cuisine American
Calories 391
5 from 2 votes

Ingredients 

Instructions 

  • Adjust an oven rack to the middle position and preheat to 450 degrees. Coat a 2 1/2-quart casserole dish with nonstick spray.
  • In a Dutch oven or large pot, bring 4 quarts water and 1 tablespoon salt to a boil. Add cauliflower and cook until tender, 3 to 4 minutes. Do not overcook. Transfer to a colander and rinse with cold water to stop the cooking. Drain well.
  • Meanwhile, melt butter in a large skillet over medium-high heat until the foaming subsides. Stir in shallots and cook until softened, about 2 minutes. Stir in garlic and thyme until fragrant, about 30 seconds.
  • Stir in flour and cook until lightly browned, about 1 minute. Whisk in cream, Parmesan cheese, nutmeg, and salt and pepper to taste (I like 1 teaspoon kosher salt and ½ teaspoon pepper). Bring to a boil; reduce heat and simmer until thickened, 1 to 2 minutes.
  • Off the heat, add cauliflower and toss to coat. Pour into the prepared baking dish and top with breadcrumbs. Bake until hot and bubbly, about 12 to 15 minutes. Serve immediately.

Notes

  1. Cauliflower: Seek out a head of this cruciferous vegetable that’s about 3 pounds and in any color. Use a knife to slice the cauliflower into bite-sized florets. 
  2. Cheese: Ideally, start with a block of Parmesan (gruyère cheese works well too) and use a box grater or pulse in a food processor to shred it yourself. Pre-shredded cheese can contain ingredients that prevent the cheese from melting as smoothly as it does fresh from the brick. 
  3. Nutmeg: Just a pinch of this spice cabinet staple lends an earthy, nutty sweetness. I rely on nutmeg as my secret ingredient in many white sauce recipes to add unexpected complexity.
  4. Bread crumbs: Start with ½ cup from a carton of store-bought bread crumbs, or to make your own bread crumbs, to a food processor, add 2 pieces of torn bread. Pulse 3 or 4 times, then let the machine run for a few seconds for coarse crumbs or a little longer for fine crumbs.
  5. Yield: This Cauliflower Gratin recipe makes six 1-cup servings; ideal to enjoy as a hearty comfort food side dish.
  6. Storage: Store leftovers covered in the refrigerator for up to 4 days.
  7. Make ahead: Prepare the Cauliflower Gratin through Step 4, then pour the mixture into a casserole dish, cover, and refrigerate for up to 2 days. When ready to bake, top with bread crumbs, and continue with Step 5. 

Nutrition

Serving: 1 cupCalories: 391kcalCarbohydrates: 18gProtein: 12gFat: 31gSaturated Fat: 19gPolyunsaturated Fat: 1gMonounsaturated Fat: 9gTrans Fat: 1gCholesterol: 106mgSodium: 419mgPotassium: 527mgFiber: 4gSugar: 4gVitamin A: 1191IUVitamin C: 70mgCalcium: 279mgIron: 2mg
Did you make this recipe?Tag @culinaryhill on Instagram so we can admire your masterpiece! #culinaryhill
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Meggan Hill is a classically-trained chef and professional writer. Her meticulously-tested recipes and detailed tutorials bring confidence and success to home cooks everywhere. Meggan has been featured on NPR, HuffPost, FoxNews, LA Times, and more.

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