Perfectly balanced and baked to golden perfection, this Cauliflower Au Gratin is a modern, lighter twist on the classic French dish. Easy enough for cozy weeknights yet decadent enough to earn a spot on your Thanksgiving menu. Tender cauliflower is smothered in a rich, creamy Parmesan sauce and topped with beautifully melted cheese, giving you all the comforting flavors of traditional Potatoes Au Gratin without the heaviness. One bite and this irresistible side dish just might become your new favorite!
Olivia’s Personal Note
You’re going to fall in love with this Cauliflower Au Gratin because it delivers all the cozy, cheesy comfort of a classic gratin without feeling heavy.
The cauliflower turns irresistibly tender in the oven, soaking up that creamy Parmesan sauce, while the golden, bubbly cheese on top adds the perfect finishing touch.
It’s elegant enough for your Thanksgiving table, especially alongside turkey breast, honey garlic pork tenderloin, reverse seared prime rib or a simple green salad. Yet easy enough for any weeknight.
Warm garlic bread are perfect for scooping up every creamy bite, making this dish truly the best of both worlds.
For the holidays, it pairs beautifully with classics like sausage stuffing, cranberry sauce, maple bacon Brussels sprouts, and mashed potatoes, rounding out a comforting and festive Thanksgiving spread.
Key Ingredients
Butter: I prefer using unsalted butter for this recipe. After testing it with salted butter, I’ve found the dish can get a little too salty since the cheese already brings plenty of seasoning. Unsalted lets you control the flavor perfectly.
Cauliflower: You’ll need one large head of cauliflower, cut into small florets. I’ve tried cutting them larger before, but smaller florets cook more evenly and absorb the creamy sauce better. They also give the gratin a smoother, more cohesive texture.
Cream: I’ve made this gratin with heavy cream, half-and-half, and even whole milk. Heavy cream gives the richest, silkiest sauce, while half-and-half keeps it creamy but a bit lighter. Whole milk works too, but I’ve found the sauce is slightly thinner. Still delicious if you want a lighter option.
Parmesan Cheese: Finely grated Parmesan adds that beautiful nutty, salty flavor and helps the sauce thicken. I’ve tested it with pre-grated Parmesan and fresh, and fresh Parmesan definitely melts better and gives a smoother finish.
Shredded Cheese: I’ve tried this recipe with Gruyère, Gouda, Swiss, and sharp cheddar and the gratin turns out creamy and decadent every single time. Gruyère melts beautifully and gives a classic French flavor, while cheddar adds a bolder, sharper taste.
Instructions To Make Cauliflower Au Gratin
- Before you begin, preheat the oven to 375°F (190°C).
- Then, grease a baking dish with butter or cooking spray.
1: Bring salted water to a boil. Add the cauliflower florets and cook for 5 to 7 minutes until it is fork fork-tender but still slightly firm. Drain and set aside.
2: In a skillet, heat the olive oil over medium heat and cook the onions until they become translucent and slightly caramelized.
3: In a medium bowl, combine the heavy cream or half and half and grated parmesan.
4: Stir or whisk in the Italian seasoning, salt, and pepper, mixing everything well.
5: Arrange the cooked cauliflower florets in the greased baking dish or a casserole dish. Spoon the caramelized onions on top of the cauliflower.
6: Spread the cheese mixture on top of the cauliflower florets.
7: Evenly sprinkle the Parmesan cheese on top. Place the baking dish in your preheated oven and bake until the cauliflower is fully tender.
8: Remove the baking dish from the oven and let it sit for a few minutes before serving. Once it is slightly cooled, the cauliflower au gratin is ready to serve
Olivia’s Recipe Tips
For picture-worthy bubbly cheese, you can turn the broiler on high for the last 3 minutes. Just remember to keep an eye on it, as the broiler works quickly!
I recommend shredding your own cheese, as it gives a much smoother, creamier finish than pre-shredded cheese.
Cut your cauliflower florets into equal-sized pieces so they all cook evenly.
Add an extra layer of flavor to this dish by roasting your cauliflower instead of boiling it. Follow my parmesan roasted cauliflower recipe for step-by-step- instructions.
Allow the cauliflower au gratin to sit for several minutes before serving. This will help the sauce thicken just a bit and keep everything together when it’s time to serve.
More Cauliflower Side Dish Recipes
Cauliflower Au Gratin
Ingredients
- 1 teaspoon butter to grease a baking sheet
- large cauliflower head cut into small florets
- 1 tablespoon extra virgin olive oil
- 1 cup white or yellow onion finely chopped
- 1 cup heavy cream or half-half cream
- ½ cup finely grated parmesan
- ½ teaspoon Italian seasoning
- Salt and black pepper to taste
- 1 cup shredded gruyere or gouda cheese
Instructions
- Preheat your oven to 375°F (190°C) and grease a baking dish (approximately 9×13 inches) with butter or cooking spray.
- In a large pot, bring water to a boil. Add a pinch of salt and the cauliflower florets. Cook the cauliflower for about 5-7 minutes or until they are tender but still slightly firm. Drain the cauliflower and set it aside.
- In a skillet, heat the olive oil over medium heat. Add the onions and sauté them until they become translucent and slightly caramelized, which should take about 5 minutes.
- In a medium bowl, add heavy cream or half-half cream, grated parmesan, Italian seasoning, salt and black pepper to taste. Mix everything well.
- Arrange cauliflower florets in the greased baking dish. Add the caramelized onions on top of the cauliflower and then, pour the creamy parmesan sauce over the cauliflower and onions. Make sure that the sauce is evenly distributed.
- Sprinkle the shredded gruyere or gouda cheese on top of the cauliflower.
- Place the baking dish in the preheated oven and bake for about 20-25 minutes or until the cauliflower is tender and the cheese is bubbly and golden brown. Enjoy!
Notes
- To Store: Keep in the refrigerator for up to 4 days in a covered baking dish or airtight container.
- To Freeze: Store in a freezer-safe container and freeze for up to 2 weeks.
- To Reheat: Reheat in the microwave or oven at 350°F.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
Did You Make This?
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This looks amazing. Have never tried before but will make soon. Will be a great side for
Thanksgiving or any dinner!
I’m sure you will love it!
It is about the Recipe instructions what are the measurements how much mild 1 cup or 2 cups or a pint.. Pretty Bad
The recipe instructions and measurements are in the recipe box at the bottom of the post. Just scroll down, and you’ll see them.