If you’re looking to elevate a simple vegetable side dish into something truly spectacular, this Broccolini au Gratin Recipe is your new go-to. It beautifully combines tender broccolini with a rich, creamy cheese sauce that’s perfectly baked to golden, bubbly perfection. The delightful crunch of toasted panko on top adds texture that will have everyone reaching for seconds. This dish strikes the perfect balance of fresh greens, savory cheese, and a hint of mustard that makes it feel both comforting and sophisticated at once. Trust me, once you try this Broccolini au Gratin Recipe, it will become a cherished staple at your table for every occasion.

Ingredients You’ll Need

A spread of various fresh and prepared ingredients arranged neatly on a white marbled surface. On the right, a large white plate is filled with vibrant green broccolini, its stalks thick and florets dense. Surrounding it are small white and gray bowls holding pale yellow butter cubes, light beige flour, golden olive oil, shredded pale yellow cheese, white breadcrumbs, thinly sliced light purple shallots, chopped garlic, a dollop of grainy mustard, and light brown seasoning powder. There are also fresh green herb sprigs placed to the far left, beside small bowls of salt and cracked black pepper. photo taken with an iphone --ar 4:5 --v 7

These ingredients are wonderfully straightforward yet each plays a vital role in making your Broccolini au Gratin Recipe taste incredible. From the fresh broccolini and aromatic shallot to the creamy blend of Gruyère and Parmesan cheeses, each element enhances the overall flavor, texture, and color in a unique way.

Broccolini (1½ pounds): Fresh and tender, this green vegetable is the star of the dish, bringing both flavor and a beautiful vibrant color.
Extra-virgin olive oil (2 tablespoons): Adds richness and helps to roast the broccolini while infusing subtle fruity notes.
Salted butter (5 tablespoons): Essential for making the creamy cheese sauce and browning the panko breadcrumbs.
Panko breadcrumbs (¾ cup): Provides the irresistible crunchy topping that contrasts perfectly with the creamy interior.
Shallot (1 large, thinly sliced): Offers a delicate sweetness and depth of flavor when sautéed gently.
Garlic cloves (2, finely chopped): Infuses the dish with savory warmth and aroma.
All-purpose flour (3 tablespoons): Thickens the sauce to achieve that luscious au gratin texture.
Whole milk (1½ cups): Creates the creamy base for the cheesy sauce without overpowering the flavors.
Whole grain mustard (1 tablespoon): Adds a subtle tang and complexity that sets this recipe apart.
Kosher salt (½ teaspoon): Enhances all the natural flavors beautifully.
Freshly cracked black pepper (½ teaspoon): Brings a gentle heat and earthiness.
Ground nutmeg (¼ teaspoon): Adds a warm, nutty undertone that harmonizes with the cheese sauce.
Fresh thyme (1 teaspoon, minced): Infuses a herby brightness that complements the richness.
Parmesan cheese (¾ cup grated): Offers a salty, tangy bite and perfect melting quality.
Gruyère cheese (1 cup grated): Melts beautifully to create that creamy, smooth texture that’s signature in gratins.
Fresh flat-leaf parsley (1 tablespoon, minced, optional): A fresh garnish that adds a pop of color and brightness to the final dish.

How to Make Broccolini au Gratin Recipe

Step 1: Roast the Broccolini

Start by preheating your oven to 400°F and placing a rack in the center position. Toss the trimmed broccolini with a tablespoon of olive oil, then spread it evenly in a shallow 3-quart baking dish. Roast the broccolini for about 10 minutes until it becomes bright green and slightly tender. This step brings out the broccolini’s natural sweetness and adds a subtle roasted depth to the final gratin.

Step 2: Toast the Panko Breadcrumbs

While the broccolini roasts, melt 2 tablespoons of salted butter in a small skillet over medium heat. Add the panko breadcrumbs and toss them to coat thoroughly with butter. Keep stirring occasionally until the breadcrumbs turn golden brown and fragrant. These toasted crumbs will create the perfect crunchy topping that contrasts beautifully with the creamy interior of the gratin.

Step 3: Prepare the Cheese Sauce

In a large skillet, heat the remaining tablespoon of olive oil over medium heat until shimmering. Add the thinly sliced shallots and cook for about three minutes until softened, stirring frequently. Toss in the garlic and cook for another minute until fragrant. Next, melt the remaining 3 tablespoons of butter into the skillet, then sprinkle the flour over the mixture. Whisk constantly for one to two minutes to cook out the raw flour taste and create a smooth roux. Slowly whisk in the milk and keep stirring until the sauce thickens nicely, about 4 to 5 minutes. Finally, stir in the whole grain mustard, salt, pepper, nutmeg, thyme, half of the Parmesan, and three-quarters of the Gruyère. Cook for a few more minutes to let the cheeses melt fully, then remove from heat.

Step 4: Assemble and Bake the Gratin

Pour the creamy cheese sauce evenly over the roasted broccolini in the baking dish. Sprinkle the remaining Parmesan and Gruyère on top, then bake in the preheated oven until the sauce is bubbling and the cheese topping has developed a light golden crust, approximately 25 to 30 minutes. After baking, let the gratin rest for about 10 minutes to allow the flavors to meld and the sauce to set slightly.

Step 5: Finish with Panko and Parsley

Just before serving, sprinkle the toasted panko breadcrumbs and minced fresh parsley over the gratin. This final touch adds inviting color, freshness, and a delightful crispy texture that makes this Broccolini au Gratin Recipe truly unforgettable.

How to Serve Broccolini au Gratin Recipe

A shiny oval metal pan filled with layers of bright green broccolini stems and fluffy white sauce mixed with small flecks of seasoning, all topped with scattered light yellow shredded cheese. The broccolini is placed evenly on top of the sauce, making a contrast of vibrant green and creamy white. The pan is set on a white marbled surface. photo taken with an iphone --ar 4:5 --v 7

Garnishes

Fresh parsley is a classic garnish that adds a burst of vibrant green and a mild herbal note to your gratin. For extra flair, you could also sprinkle finely grated Parmesan just before serving to enhance that cheesy goodness. A light drizzle of extra-virgin olive oil can also add a subtle sheen and richness.

Side Dishes

This Broccolini au Gratin Recipe pairs beautifully with roasted chicken, grilled salmon, or even a hearty steak. It’s a wonderful side that brings brightness and elegance to any meal. For a vegetarian-friendly plate, serve alongside a robust grain like quinoa or a lentil salad for a complete, satisfying dinner.

Creative Ways to Present

For a special gathering, consider preparing the gratin in individual ramekins for a charming personal touch. If you’re hosting a buffet, serving the gratin in a large shallow dish allows guests to help themselves to this cheesy delight. You can even sprinkle a few toasted pine nuts on top for an extra crunch and a subtle nutty flavor that elevates the dish further.

Make Ahead and Storage

Storing Leftovers

After enjoying your Broccolini au Gratin Recipe, store any leftovers in an airtight container and refrigerate for up to 3 days. The flavors will mellow and blend beautifully, making for delicious next-day meals.

Freezing

If you want to save some for later, this gratin freezes well. Place it in a freezer-safe container before baking or freeze the fully baked dish once cooled. It should keep its delicious texture and flavor for up to 2 months, making it a fantastic make-ahead option.

Reheating

To reheat, place the gratin in an oven-safe dish and warm at 350°F for 15 to 20 minutes until heated through and bubbly. Reheating in the oven helps restore the crispy top, but you can also use a microwave for convenience, though the topping may be softer.

FAQs

Can I use regular broccoli instead of broccolini?

Absolutely! While broccolini has a slightly sweeter and more delicate flavor, regular broccoli works perfectly in this Broccolini au Gratin Recipe. The cooking times might vary slightly since broccoli florets are thicker, so keep an eye on them while roasting.

What can I substitute for Gruyère cheese?

If Gruyère is hard to find, you can use other good melting cheeses like mozzarella or fontina. They won’t have quite the same nutty flavor, but they’ll keep the creamy, cheesy texture that makes this gratin so comforting.

Is this recipe suitable for vegetarians?

Yes, this Broccolini au Gratin Recipe is vegetarian-friendly as long as you use vegetarian Parmesan (without animal rennet). It’s a wonderful way to enjoy a cheesy, hearty vegetable dish without any meat.

Can I prepare this recipe dairy-free?

It’s a bit challenging because the cheese is central to the gratin’s flavor and texture. However, you can experiment with dairy-free milk alternatives and vegan cheese substitutes, though the final taste will differ from the traditional version.

How can I make this dish gluten-free?

Swap out the all-purpose flour for a gluten-free flour blend when making the sauce, and use gluten-free breadcrumbs or crushed nuts for the topping. The rest of the ingredients are naturally gluten-free, so the dish will remain just as tasty.

Final Thoughts

This Broccolini au Gratin Recipe is a true crowd-pleaser that transforms a humble vegetable into something luxuriously comforting and flavorful. Whether you’re cooking for a family dinner or a special occasion, it’s guaranteed to impress with its creamy cheese sauce, tender broccolini, and irresistible golden topping. I can’t recommend giving this recipe a try enough — it just might become your new favorite side dish to serve again and again.