Creamy, cheesy, with the crunchiest breadcrumb Parmesan topping, this Broccoli au Gratin is an impressive holiday side that’s secretly simple to prep ahead of time! The broccoli florets are roasted instead of boiled or steamed for the best texture and the least amount of dishes to clean.
London’s top tips to make it a winner: Use a fresh head of broccoli instead of the pre-packaged kind for the best flavor. Also, a pinch of nutmeg adds a special depth of flavor to the creamy Gruyère cheese sauce.
Table of Contents
Thanksgiving is by FAR my favorite food holiday of the year. From the sweet potato casserole with a pecan topping, Cajun cornbread dressing (a Southern must in our house!), and green bean casserole—I look forward to this spread of sides all year long!
While the holidays are rooted in tradition, I can’t resist adding one or two new recipes to the table each year. Who knows, maybe we’ll start a new one!
This year, I’m introducing a veggie-forward dish that I think is going to steal the spotlight… Broccoli au Gratin! (A spin-off of this Cauliflower au Gratin that was such a hit last year!) Despite its fancy name, it’s super simple to make. You can think of it more like a cheesy broccoli casserole. You’ll roast the broccoli right in the baking dish, avoiding watery results, and then top it with a rich Gruyère cheese sauce and crunchy breadcrumbs.
Ingredients You’ll Need
For the exact measurements and detailed instructions, you can jump to the recipe.
- Broccoli. You’ll need 1½ pounds of broccoli florets (about 2 large heads before trimming, weighing close to 2 pounds). Cut florets into florets about 1 to 1 ½ inches in diameter for the best results.
- Cheese. Gruyère is my top pick for its nutty, slightly salty flavor, but feel free to use sharp white cheddar, fontina, or Swiss if you prefer or can’t find Gruyère.
- Flour. All-purpose flour combines with butter to form a roux that will help thicken the sauce.
- Milk. Whole milk gives the creamiest results, though 2% or a plant-based milk can be used with a slightly different texture.
- Dried Herbs. Dried thyme brings a warm flavor to the dish. For a twist, try dried rosemary or even fresh thyme (use 2–3 times the amount if fresh).
- Breadcrumbs. Regular breadcrumbs (not panko) create the best texture. I used Aleia’s for their minimal salt content. If your breadcrumbs are saltier, consider reducing the salt in the recipe by ¼–½ teaspoon.
- Parmesan Cheese. Grated Parmesan, whether freshly grated or pre-packaged, mixes perfectly with the breadcrumbs and butter for a deliciously crisp topping.
How to Make Broccoli au Gratin
Jump to the recipe for the full instructions, ingredient amounts, and a printable recipe.
- Roast the broccoli. Add the broccoli florets to a baking dish. Drizzle the pieces with olive oil, salt, and pepper. Toss to combine, then bake at 425°F for 10 to 12 minutes. The broccoli should be bright green with a few brown edges.
- Make a roux. While the broccoli is roasting, melt the butter in a skillet, then heat the garlic for 30 seconds. Sprinkle the flour over the butter and mix until a thick paste forms. Continue to whisk until it thins out again.
- Make the sauce. Turn the heat down to medium-low, and slowly pour the milk into the mixture ¼-cup at a time. Let the sauce thicken before adding more.
- Add the cheese. Take the pan off the heat, then stir in the Gruyere cheese along with the seasonings. Pour the sauce over the broccoli, being sure to lift up the broccoli pieces to spread it well.
- Add the topping. Stir together melted butter, Parmesan cheese, and breadcrumbs in a small bowl. Sprinkle the topping over the cheesy broccoli.
- Bake in the oven. Bake the broccoli au gratin in the oven for another 20 to 25 minutes until the topping is golden and the broccoli is fork-tender.
FAQs
Yes, you can use frozen broccoli if fresh isn’t available, but be sure to thaw and pat it dry thoroughly to prevent excess water in the dish. You will also only need to bake it for 5 minutes since it’s blanched before freezing. (Fresh broccoli will yield the best texture, especially with the roasting step.)
Absolutely! You can assemble the dish, cover it, and refrigerate it for up to 1 day in advance. When ready to bake, allow it to sit at room temperature for about 20 minutes, then bake as directed.
Yes, sharp white cheddar, fontina, or Swiss cheese work well as substitutes if Gruyère is unavailable. Each will add its own unique flavor!
To make the dish gluten-free, use a gluten-free all-purpose flour blend for the sauce and gluten-free breadcrumbs for the topping.
More Thanksgiving Side Dish Recipes
Take your turkey day up a notch with these tasty side dishes!
Tap stars to rate!
Broccoli au Gratin Recipe
email this recipe!
Ingredients
- 1 ½ pounds broccoli florets from 2 large heads*
- 1 ½ teaspoon salt divided
- ¾ teaspoon black pepper divided
- 2 tablespoons olive oil
- 3 tablespoons salted butter
- 2 garlic cloves finely minced
- 2 tablespoons all-purpose flour
- 1 ½ cups whole milk
- 1 cup shredded Gruyere cheese
- 1 teaspoon dried thyme
- Pinch nutmeg optional
- ¼ cup breadcrumbs plain*
- ¼ cup grated parmesan cheese
Instructions
- Preheat the oven to 425°F.
- Add the broccoli florets to a 7×10-inch or 9×9-inch baking dish that has been sprayed with non-stick cooking spray. Drizzle with the olive oil and sprinkle with 1 teaspoon salt and ½ teaspoon black pepper. Toss to combine and spread broccoli out in a flat layer. Bake for 10-12 minutes, or until broccoli is bright green and some edges begin to brown. (It does not need to be cooked all of the way through just yet!)1 ½ pounds broccoli florets, 2 tablespoons olive oil
- Add 2 tablespoons of the butter to a large skillet over medium heat. Once melted, add the garlic and cook for 30 seconds, or until fragrant. Sift in the flour and immediately begin whisking for 1-2 minutes, or until it forms a thick paste. Continue whisking for 1 more minute, or until it begins to thin out again.2 garlic cloves, 2 tablespoons all-purpose flour
- Reduce the heat to medium-low. In ¼ cup increments, pour in the milk, whisking well after each addition and waiting for the sauce to slightly thicken between each one.1 ½ cups whole milk
- Remove from the heat and add the gruyere cheese, ½ teaspoon salt, ¼ teaspoon black pepper, thyme, and nutmeg. Pour the sauce over the broccoli, lifting up the florets as you do so it spreads throughout.1 cup shredded Gruyere cheese, 1 teaspoon dried thyme, Pinch nutmeg
- Melt the remaining 1 tablespoon butter in a small bowl. Add the Parmesan cheese and breadcrumbs. Toss until well mixed and then sprinkle over the broccoli.¼ cup breadcrumbs, ¼ cup grated parmesan cheese
- Bake in the oven for 20-25 minutes, or until the topping is golden and the broccoli is fork-tender. Serve with fresh thyme, if desired.
Tap stars to rate!
Notes
- Broccoli. You’ll need 1½ pounds of broccoli florets (about 2 large heads before trimming, weighing close to 2 pounds). Cut florets into florets about 1 to 1 ½ inches in diameter for the best results.
- Cheese. Gruyère is my top pick for its nutty, slightly salty flavor, but feel free to use sharp white cheddar, fontina, or Swiss if you prefer or can’t find Gruyère.
- Milk. Whole milk gives the creamiest results, though 2% or a plant-based milk can be used with a slightly different texture.
- Breadcrumbs. I used Aleia’s for their minimal salt content. If your breadcrumbs are saltier, consider reducing the salt in the recipe by ¼–½ teaspoon.
- Storage: Store leftovers in an airtight container in the refrigerator for up to 4-5 days. Freezing is not recommended as the texture will change upon thawing.
- Reheating: Return the dish to a 350°F oven for 5-10 minutes, or warm up in a skillet over medium-low heat.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
