Ultimate Sheet Pan Broccolini Au Gratin

This twist on the classic Potatoes Au Gratin substitutes the potatoes for tender and crispy broccolini, making it the perfect way to get in an extra serving of veggies. This is my Ultimate Sheet Pan Broccolini Au Gratin, and it is perfectly creamy, cheesy, and crispy in every bite. Made from just a few simple ingredients, this dish is packed with flavor and is perfect for serving at your next holiday dinner.

When I shared my Ultimate Sheet Pan Potatoes Au Gratin last year, THOUSANDS of you made it and tagged me in your recipes. Nothing makes me happier than when I get to see your renditions of the recipes that my team and I work so hard to create. Part of what I love so much about food is that it brings people together, and seeing you share my recipes with your loved ones and form new traditions absolutely warms my heart. Which is why, when I see so many of you making a recipe over and over again, I am always determined to find new ways to improve it.

This year, I am so excited to be sharing my Ultimate Sheet Pan Broccolini Au Gratin. It’s everything that you know and love about my Potatoes Au Gratin, but made even BETTER by substituting the potatoes for broccolini. If you’re someone who struggles to get enough veggies into their diet, or if you’re a parent to picky little ones, then this is a recipe to keep in your back pocket. After all, who could hate broccolini when it’s smothered in cream and cheese? Think of this recipe as an elevated, grown-up take on the classic broccoli with cheese. It’s familiar enough to still be comforting, while also being refined enough to serve at your Thanksgiving dinner table. If you’re looking for a super easy side dish to prepare ahead of the holidays, then look no further because this is it!

“But Nicole, why should I use a sheet pan?”

While traditional Au Gratins (which translates to “topped with cheese”) are made in a deep casserole dish, my secret to making this recipe is to prepare it on a sheet pan. Why? Well, for starters, the sheet pan is thinner, which allows the broccolini to cook in one even layer. The end result is is a Broccolini Au Gratin where every single bite is perfectly crispy!

No more fighting over the crispy bits on top, or getting stuck with a soggy serving from the bottom. Instead, by cooking this recipe on the sheet pan, it ensures that every single bite is just as crispy and delicious.

What You Need to Make This Sheet Pan Broccolini Au Gratin

• Broccolini: Of course, it wouldn’t be a Broccolini Au Gratin without the broccolini! I like to get my broccolini from Trader Joe’s because it’s already chopped and ready-to-go!
• Olive Oil: Olive oil not only helps to get the broccolini to its perfect consistency, but also adds a delicious flavor to this recipe. You can also opt to use avocado oil, if you prefer.
• Cheese: This recipe comes together with a cheesy blend of gruyere, parmesan, and white cheddar cheeses. Yum!
• Butter: Because Potatoes Au Gratin (which this recipe is inspired by) is known for having a creamy and buttery sauce, butter is an essential ingredient in this recipe. Both dairy and non-dairy butter work just as well.
• Garlic and Shallot: The combination of fresh garlic and shallot is truly unbeatable and adds the best flavor to this dish. Don’t skip it!
• Heavy Cream: The thick, creamy sauce comes together with a base of heavy cream. You can use a dairy-free heavy cream alternative if you prefer, however I prefer to use dairy cream, as it leads to the best results.
• Flour: A little flour will help to thicken the sauce, so that it reaches the perfect consistency.
• Seasonings: To season this Broccolini Au Gratin, you’ll need a combination of fresh thyme, nutmeg, sea salt, and ground black pepper. Yum!
• Lemon Zest: This recipe ONLY requires the zest of one lemon, not the juice! Otherwise, it will be way too lemony for your liking, and may lead the cream to curdle.
• Panko Breadcrumbs: The key to making an “au gratin” is a crispy top, and for this recipe, it comes together with delicious, golden, panko breadcrumbs. You can also opt to use gluten-free breadcrumbs, if you prefer!

How to Make This Cozy & Creamy Broccolini Au Gratin

To make this dish, start by preheating your oven to 400 F. Next, prepare the broccolini. Spread the broccolini across a gently-greased sheet pan. Pour the olive oil on top of the broccolini and toss to fully coat. Then, transfer the tray into the oven and allow the broccolini to bake for 10 minutes.

While the broccolini is baking, prepare the sauce. Grate the cheeses (the gruyere, white cheddar, and parmesan) into a small bowl and set it aside. Next, heat a saucepan, on the stove, over medium heat, and add in the butter. Dice the garlic and shallot. Then, once the butter has melted, add the garlic and shallot to the pan and sauté them 2 minutes. Then, add in the heavy cream, flour, thyme, nutmeg, sea salt, ground black pepper, and lemon zest to the pan. Stir to combine.

Bring the mixture to a gentle boil. Then, reduce the heat to low, cover, and allow the sauce to simmer for another 2 minutes. Once the broccolini is done, remove it from the oven and sprinkle half of the cheese mixture on top of it, followed by the creamy sauce mixture. Then, sprinkle the remaining cheese across the top.

Then, add the panko breadcrumbs across the top of the broccolini, spreading them out into an even layer. Finally, cover the tray with foil and place it back into the oven to bake for 20 minutes. Then, remove the foil and cook for another 15 minutes, until the top of the broccolini is bubbly and the panko breadcrumbs are crispy and golden. Once the broccolini is done, serve it immediately and enjoy!

A Few Tips for Preparing This Dish

• To prepare ahead time: If you want to prepare this dish ahead of time, follow steps 1-11 of the recipe, as directed below. Then, once the broccolini has been cooked for 20 minutes, remove it from the oven and allow it to cool, keeping the foil on top of the pan. Transfer the pan into the fridge. Then, once you’re ready to serve it, heat your oven to 400 F, remove the foil from the pan, and follow steps 11-13 in the recipe card. That’s it!
• To make this recipe gluten-free: If you want to make this recipe gluten-free, you can use a 1:1 gluten-free baking flour to thicken the sauce and replace the panko breadcrumbs with a gluten-free alternative. It’s that easy!
• To store leftovers: To store any leftovers, transfer them to an airtight container and place them in the fridge for up to three days.

If you make this recipe, please be sure to leave a review and rating below! To see more recipes and behind the scenes, follow along on Instagram, TikTok, and Youtube! I’m also now on Pinterest, so stop by and take a look at what’s new.

** Photography by Tanya Pilgrim