The Best Broccoli au Gratin recipe! Broccoli is tossed in garlic for lots of amazing flavors, oven roasted (not steamed or boiled!) and topped with creamy béchamel cheese sauce along with breadcrumbs and parmesan cheese.
This cheesy broccoli casserole recipe is perfect for the Thanksgiving and Christmas holidays…or as a side to dinner any day. Trust me – even non veggie eaters will LOVE this Broccoli au Gratin recipe!
Looking for more vegetable dishes? Don’t forget to also check out my Garlic Parmesan Asparagus, Garlic Sautéed Spinach, Roasted Lemon Garlic Broccoli, Caramelized Onions Sautéed Green Beans, Fresh Green Bean Casserole, and Roasted Zucchini with Garlic Parmesan. We are all about making simple vegetables taste AMAZING.
One reader, Debi, commented: “I love broccoli side dishes! So when I saw it I knew I had to make it right away. Easy to make and so delicious! Thanks for the recipe!★★★★★”
One reader, Jennifer, commented: “Broccoli is my go-to veggie of choice and you just blew my mind with this recipe! The parmesan cheese goes great with the broccoli and it’s got a richness that I love!★★★★★”
Why I Love This Recipe
This, my friends, is the BEST Broccoli au Gratin recipe.
I don’t use the word ‘best’ lightly. What sets this recipe apart is that we season and roast the broccoli (no boiling or steaming so that broccoli is not soggy!), before topping it with a creamy cheese sauce that is flavorful but not overly heavy.
When I was setting out to develop a solid broccoli au gratin recipe, I tested it by blanching the broccoli first because that’s what the classical broccoli au gratin recipe calls for, and decided that roasting it is a much better way to retain incredible texture and bring more flavors to the broccoli.
Our Broccoli au Gratin comes out flavorful, has great textures, and broccoli is not drowning in cheese sauce. In fact, the cheese sauce is there to highlight the broccoli.
My hope is that even non-broccoli lovers will fall in love with broccoli au gratin. Because it is that good!
What is au Gratin?
Au Gratin is a French culinary technique where a dish is baked and topped with cheese and breadcrumbs, then broiled briefly so that it is golden brown and bubbly on top. It can be made with potatoes, cauliflower, tomatoes, and of course, broccoli.
Think of it as a lighter, more sophisticated take on the classic broccoli bake.
But let’s be real here, you can pretty much bake anything with that cheese sauce and it’s gonna taste amazing. 😉
Broccoli au Gratin is such a yummy vegetable side dish that serves well with protein dishes such as ham, beef, chicken, or pork. Being rich and creamy in nature, it also makes a delicious and impressive holiday or entertaining veggie dish.
Ingredients
To make Broccoli au Gratin, gather up these ingredients!
- Broccoli florets: I use fresh, but you can use frozen. If using frozen, let it defrost and pat it dry before tossing in the seasoning to oven bake.
- Minced garlic: Fresh garlic is always the best. In a pinch, garlic powder works as well, but it will never be as good as fresh!
- Salted butter: Melted with the flour to start the creamy béchamel sauce.
- All-purpose flour: Thickens the sauce.
- Milk: 2% or higher is preferred for a creamy sauce.
- Breadcrumbs: Used as the crunchy topping.
- Parmesan cheese: Used as topping. Grated parmesan cheese is preferred, not shredded.
- Salt and black pepper: Seasons both the broccoli and the sauce.
- Cooking oil: Any neutral oil such as olive oil, avocado oil, canola oil or vegetable oil works well for roasting.
Let’s Make this Cheesy Broccoli Casserole!
Step 1: Season and Oven Bake Broccoli
If you purchased a large broccoli head, cut it into small florets before tossing it in cooking oil, garlic, salt and black pepper.
Bake them on a baking sheet lined with parchment paper (for easy cleanup) at 350°F for 15 minutes. If you like your broccoli softer, you can bake for longer.
When done baking, transfer the roasted broccoli to a greased 12-inch oval gratin dish, or an 8×8-inch (or 9×9-inch) square casserole dish.
At this point the broccoli shouldn’t be fully cooked, but cooked partially, and it will be baked in the oven again later to finish cooking.
Step 2: Make Béchamel Sauce
Next, we are going to make the creamy white béchamel sauce that will be going on top of the Broccoli au Gratin. The same white béchamel sauce is also used in our Classic Lasagna with Béchamel Sauce recipe.
In a pot under medium heat, bring together butter and flour, then add milk.
Bring to a boil, and whisk continuously until there are no more flour clumps in the sauce. At this point the sauce should also thicken slightly.
Remove from heat promptly, and avoid overcooking and over-thickening the sauce.
If the sauce is thicker than desired, add more milk to thin it out.
Step 3: Assemble and bake
Once the sauce is ready, pour it over the top of the broccoli casserole.
I go pretty light on the sauce (it just coated the top of the broccoli) because I don’t want to overpower my Broccoli au Gratin dish with too much cream. If you’d like a creamier, richer sauce, double the sauce recipe.
Then top it with breadcrumbs and parmesan cheese.
Lastly, send this broccoli bake to the oven!
This time we are baking it at 425°F for 20 minutes, and then broiling it for 3 minutes until the top is slightly crusty and golden brown.
TA-DA!!! Check out the ooey gooey goodness….
Broccoli is still slightly crunchy on the outside, but soft on the inside, and perfectly seasoned with garlic. It is then coated with a light creamy béchamel sauce and topped with a crusty golden brown parmesan breadcrumbs topping.
Whether you like broccoli or not, this Broccoli au Gratin dish is about to rock your world!
It’s filled with amazing flavors and textures, and makes eating broccoli FUN!
Make Ahead and Freezing
Broccoli au Gratin is easy to prep ahead. Here are two ways to do it:
Assemble ahead: Roast the broccoli, make the sauce, assemble the au gratin, cover and store it in the refrigerator to bake later. Bring it to room temperature 1 hour ahead of time, then bake using the recipe instructions, or until the broccoli is heated throughout. Remember to broil it at the end.
Bake ahead: Fully bake the Broccoli au Gratin, cover and store it in the refrigerator. Bring it to room temperature 1 hour ahead of time. To reheat, cover with aluminum foil and bake at 400°F for 20 minutes, or until the broccoli is heated throughout.
Freezing: Instead of refrigerating the assembled or fully baked Broccoli au Gratin, you can seal and freeze it for up to 1 month. Thaw it in the refrigerator a day ahead of time, then follow the make ahead steps above to heat and serve it.
Tips and Tricks
A few simple tricks help this Broccoli au Gratin turn out great every time.
- Roast, don’t boil: Roasting the broccoli instead of steaming or boiling it adds flavor and keeps it from getting soggy under the sauce.
- Cut evenly sized florets: Similar-size pieces cook at the same pace, so every bite is tender.
- Give the broccoli some room: It’s fine if the florets are crowded on the baking sheet, but don’t let them pile on top of each other, so they roast instead of steam.
- Pat frozen broccoli dry: If you’re using frozen broccoli, let it defrost fully and pat it dry first. Extra moisture can water down the sauce.
- Whisk constantly: Keep whisking as the béchamel comes to a boil so the flour doesn’t clump.
- Take the sauce off the heat once done: The sauce is ready as soon as it thickens slightly. Remove the pot right away, since overcooked sauce turns thick and paste-y. If it does get too thick, whisk in milk 1 tablespoon at a time.
- Season the sauce: Make sure to season the béchamel sauce with salt and black pepper to really open up the flavors.
- Let it rest a few minutes: Give this cheese broccoli casserole a short rest after baking so the sauce settles and it’s easier to scoop.
Frequently Asked Questions
Use a square casserole dish instead. Either 9′ x 9′ or 8′ x 8′ should work just fine!
Yes! If using frozen broccoli, bring it to defrost and pat dry to remove moisture before seasoning and baking it. Personally, I prefer fresh because there’s less moisture in it.
Double the cheese sauce/ bechamel sauce! Everything else should stay the same. By doing this you’ll have broccoli soaked in sauce, versus just being topped with sauce 🙂
It’s probably overcooked. Remove pot from heat promptly once sauce starts thickening. To thin it out, add 1 tbsp of milk at a time until it reaches your desired consistency.
Roasting is what gives this Broccoli au Gratin its flavor, and it keeps the broccoli from turning soggy the way boiling or steaming can. It’s also partially cooked before it goes in the oven again with the sauce.
Roast the broccoli instead of boiling or steaming it. If you’re using frozen broccoli, defrost it and pat it dry first. Go light on the sauce so it coats the top of the broccoli rather than drowning it.
Yes! You can assemble it ahead and bake it later, or bake it fully and reheat it covered with foil. You can also freeze it for up to 1 month. See the Make Ahead And Freezing section above for the steps.
They’re close cousins! Both are baked, cheesy broccoli side dishes. What makes this one an au gratin is the golden, crusty breadcrumb and parmesan topping over a light homemade béchamel. In general, it’s less rich and heavy.
What to serve with it
Broccoli au Gratin makes a delicious vegetable side dish, especially for holidays or dinner parties. I love serving this cheesy broccoli casserole with some of these delicious protein dishes:
- Pork Tenderloin with Gravy
- Garlic Rosemary Chicken
- Spicy Baked Chicken Tenders
- Pineapple Baked Ham
- Dutch Oven Herb Butter Turkey Breast
- Panko Crusted Salmon
- Honey Lemon Garlic Shrimp
- Bacon Wrapped Pork Tenderloin
- Apple Cider Braised Pork Shoulder
ENJOYED THIS RECIPE? Tell us what you think by leaving a rating and review below! 🤍
Broccoli au Gratin
Ingredients
- 1.5 lbs broccoli florets
- 2 tbsp olive oil
- 1/2 tsp salt for roasting brocolli
- 3 cloves garlic minced
- 2 tbsp salted butter
- 2 tbsp all purpose flour
- 1 cup 2% milk
- 1/2 tsp salt for sauce
- 1/4 tsp black pepper
- 2 tbsp breadcrumbs
- 1/2 cup parmesan cheese grated
Instructions
- Pre-heat oven to 350°F
- In a large bowl, toss broccoli florets in olive oil, 1/2 tsp salt and minced garlic.
- Spread broccoli on a greased baking sheet (line with aluminum foil for easy cleanup). They can be crowded together but not overlapped on top of each other.
- Bake for 15 minutes. Remove and transfer broccoli into a 12' oval baking dish (or 9' x 9' square baking dish).
- Pre-heat oven to 425°F.
- Bring a small pot to medium low heat on the stovetop. Add butter and flour. Mix to combine. Then add milk.
- Bring to a boil and whisk continuously until flour clumps disappear. When sauce thicken slightly, add 1/2 tsp salt and 1/4 tsp black pepper. Stir to combine, then remove pot from heat.
- Pour sauce and spread all over broccoli in the casserole, then top with breadcrumbs and parmesan cheese.
- Bake Broccoli au Gratin in the oven for 20 minutes, then broil for 3 minutes, or until the top is slightly golden brown. Remove from oven.
- Serve and enjoy!
Recipe Notes
- For a creamier and richer Broccoli au Gratin, double the sauce recipe.
- Avoid overcooking sauce if not it will be too thick. Remove from heat once it starts to thicken. To thin sauce, add a few tbsp of milk at a time until it reaches desired consistency.
I love broccoli side dishes! So when I saw it I knew I had to make it right away. Easy to make and so delicious! Thanks for the recipe!
I’m so glad you enjoyed it, Debi!
Loved that the broccoli was roasted! Thank you for a fabulous recipe, I always know I can find solid recipes on your site!
Thanks so much Kathi for the kind words! 🙂
Broccoli is my go-to veggie of choice and you just blew my mind with this recipe! The parmesan cheese goes great with the broccoli and it’s got a richness that I love!
Thanks for the kind words 🙂 One of my favorite ways to make broccoli for sure!
Loved this recipe! Had a really good ratio of broccoli to creamy cheese sauce and worked well in my square baking dish
So glad to hear that! Thanks for sharing!
This came out fabulous! We made it for Thanksgiving. What a great way to elevate broccoli into something else! I loved it and so did the family.
Happy to hear you all enjoyed this for Thanksgiving!
Can you use frozen broccoli for this? We live in a very rural area so running to the store for ingredients is not an option. I do have broccoli in the freezer though.
Yes that would be fine! Fresh is better but frozen works too in a pinch
Hi
Breadcrumbs are they fresh or dried? If using dried breadcrumbs are they regular breadcrumbs or panko breadcrumbs.
We are using dried breadcrumbs! I typically use regular for this recipe but panko works as well!