Broccoli Parmesan Casserole

This broccoli Parmesan casserole recipe transforms broccoli into a cozy, cheesy baked delight. The combination of earthy broccoli and nutty Parmesan is comfort food perfection. And let’s be honest: When cheese is involved, even picky eaters get excited to eat their veggies. Add a rich, creamy sauce and a crispy bread crumb topping, and you’ve got a decadent side dish that’s right at home on a Sunday dinner table or holiday spread.

Start by steaming broccoli florets until they’re crisp-tender. Then, whip up the cheesy sauce on the stovetop with butter, onion, garlic, flour, milk and Parmesan. Cover the broccoli with the sauce, top it with toasted bread crumbs, and bake the dish until golden and bubbly. This recipe makes enough to fill a standard 13×9-inch baking dish, but you can easily halve it or bake it in two smaller 8×8-inch casserole dishes. Our Parmesan broccoli casserole is also easy to make ahead, which makes it a go-to for busy weeknights or entertaining.

Ingredients for Broccoli Parmesan Casserole

• Broccoli: Use fresh broccoli florets for the best texture; frozen broccoli releases moisture when thawed, which can make the sauce watery.
• Butter: Melted butter adds richness and creates the base of the creamy sauce. If you use salted butter, you may want to decrease the amount of salt you add later.
• Onion and garlic: These aromatics add depth, a savory flavor and aroma to the sauce. Finely chop the onion and mince the garlic for a smoother sauce.
• Flour: When combined with the melted butter, all-purpose flour forms a quick roux that thickens the sauce.
• Milk: Milk is the creamy body of the sauce. This recipe calls for 2%, but you can swap in whole milk for richer flavor or use an unsweetened dairy-free alternative if needed.
• Egg yolk: A single egg yolk helps the sauce set as it bakes so the casserole has a scoopable, custard-like texture. If you need an egg-free recipe, you can skip the yolk, but your final dish will have a looser, saucier texture.
• Parmesan cheese: Freshly grate a block of Parmesan cheese for the best flavor and meltability.
• Bread crumbs: Toasted seasoned bread crumbs deliver a crunch that contrasts with the creamy elements. Store-bought bread crumbs are a timesaver, but you can make homemade bread crumbs with stale or toasted bread and dried herbs.

Directions

Step 1: Steam the broccoli

Preheat the oven to 400°F. Start by steaming the broccoli in two batches. Place half the florets in a steamer basket set over 1 inch of water in a large saucepan. Bring the water to a boil, then cover and steam for three to four minutes until the broccoli is crisp-tender. Transfer the steamed broccoli to a greased 13×9-inch baking dish, then repeat with the remaining broccoli.

Editor’s Tip: No steamer basket? No problem! You can steam the broccoli florets in a large saucepan with 1 inch of water. Cover and cook the broccoli over medium heat until it is bright green and crisp-tender, three to five minutes. Drain it well before transferring to the baking dish.

Step 2: Make the sauce

Melt 4 tablespoons of butter in a small saucepan over medium heat. Add the onion and cook, stirring frequently, until tender. Stir in the minced garlic and cook for one minute longer, just until fragrant.

Sprinkle the all-purpose flour over the onion and garlic and stir until no white remains. Slowly pour in the milk and whisk to break up any lumps. Bring the mixture to a boil. Cook for two minutes, stirring constantly, until the sauce thickens.

Step 3: Temper the egg yolk and add the cheese

Place the egg yolk in a small bowl and stir in a small amount of the hot sauce to temper it. Slowly pour the egg mixture back into the saucepan, stirring constantly. Cook for one minute longer.

Editor’s Tip: Tempering gently warms the egg yolk so it blends smoothly instead of scrambling into bits of egg when it hits the hot sauce.

Then, remove the sauce from the heat and stir in the grated Parmesan, salt and pepper. Pour the sauce over the broccoli.

Step 4: Toast the bread crumbs

Melt the remaining 2 tablespoons of butter in a small skillet over medium heat. Add the bread crumbs and stir until evenly coated in butter. Cook, stirring often, until they turn golden brown. Sprinkle over the broccoli mixture.

Step 5: Bake the casserole

Bake the broccoli Parmesan casserole, uncovered, for 15 to 18 minutes until it’s heated through and bubbly around the edges.

Recipe Variations

• Make it with other veggies: Replace half or all the broccoli with cauliflower florets or Brussels sprouts, or combine other veggies like mushrooms or baby spinach with the broccoli for added texture and flavor.
• Try another cheese: Make a gooey casserole by swapping in a melty cheese for the Parmesan. Try shredded mozzarella, sharp white cheddar or Gruyere.
• Add protein: Turn this broccoli and Parmesan casserole into a meal by adding shredded rotisserie chicken or diced ham to the baking dish.
• Give it some kick: Sprinkle smoked paprika, cayenne pepper or hot sauce into the creamy sauce for a bit of spice.
• Change the crunch: Instead of bread crumbs, try topping the casserole with french-fried onions, crushed Ritz crackers or potato chips for a salty, crunchy finish.

How to Store Broccoli Parmesan Casserole

Let the broccoli and Parmesan casserole cool completely, then cover it tightly or transfer leftovers to an airtight container and store in the refrigerator for up to four days. Reheat individual portions in the microwave or warm the casserole in a 350° oven.

Can you freeze broccoli Parmesan casserole?

You can freeze this casserole, but it’s not ideal. Since the creamy sauce contains milk and cheese, it may separate and become watery after thawing. For the best texture and flavor, we recommend enjoying it fresh and storing leftovers in the fridge.

Can you make Parmesan broccoli casserole ahead of time?

Yes, you can make Parmesan broccoli casserole ahead of time—it’s perfect for saving time on busy weeknights or holiday hosting. Assemble the casserole, but do not add the bread crumbs or bake it. Cover the baking dish and refrigerate it up to one day in advance. When ready to bake, let the casserole sit at room temperature while the oven heats up. Add the bread crumb topping just before baking and bake as directed.

Broccoli Parmesan Casserole Tips

Should you use fresh or frozen broccoli in this casserole?

Fresh broccoli is ideal for this casserole—it holds its shape and texture better after steaming and baking, giving you a tender-crisp bite. Frozen broccoli works in a pinch, but your casserole will have a softer texture. If using frozen broccoli, be sure to thaw and drain it well to avoid excess moisture in your casserole.

How can you give broccoli Parmesan casserole more flavor?

To boost the flavor of this casserole, experiment with seasonings to suit your taste. Taste the sauce after it thickens, and adjust the salt and pepper as needed. If you like spicy, add a few dashes of hot sauce or sprinkle in cayenne pepper. For extra freshness, stir in dried or fresh herbs, like thyme, parsley or chives. A bit of lemon zest can add brightness, while a pinch of ground nutmeg adds warmth without making it spicy.

What can you serve with broccoli Parmesan casserole?

Broccoli Parmesan casserole pairs perfectly with holiday favorites like stuffing, mashed potatoes, Thanksgiving turkey and glazed ham. It also works well with classic weeknight dinners like baked pork chops, meat loaf or roasted salmon. You can even add rotisserie chicken, cooked diced chicken breasts or diced ham to the casserole to make it a one-dish meal.