Parmesan Cauliflower Gratin with Garlic Breadcrumbs

Prep Time 20

Cook Time 25

Total Time 45

Course Side Dish

Cuisine American, French

Servings 6

Medium saucepan For making the béchamel (white sauce). A heavy-bottomed one prevents scorching.
Large Pot or Dutch Oven To blanch the cauliflower before baking.
8x8 or 9x9-inch baking dish (or similar-sized casserole dish) Ceramic or glass works best to hold heat and give a beautiful presentation.
Whisk For stirring the sauce and ensuring no lumps.
Wooden spoon or silicone spatula For folding in the cheese and cauliflower.
Skillet For toasting the breadcrumb topping.
Colander or slotted spoon For draining the cauliflower after blanching.

1 large head of cauliflower cut into bite-sized florets (about 6–7 cups)
2 tablespoons unsalted butter
2 tablespoons all-purpose flour
2 cups whole milk or substitute with half-and-half for extra richness
1 teaspoon Dijon mustard
1/2 teaspoon garlic powder
1/4 teaspoon ground nutmeg
Salt and freshly cracked black pepper to taste
1 cup freshly grated Parmesan cheese divided (don’t use pre-shredded — it won’t melt properly)
1/2 cup grated Gruyère or sharp white cheddar cheese optional, but adds depth

Preheat your oven to 400°F (200°C). Butter or lightly grease your baking dish and set it aside.

Bring a large pot of salted water to a boil. Add cauliflower florets and cook for 3–4 minutes, until just tender but still firm. Drain immediately and set aside. This step ensures your cauliflower is cooked through but not mushy after baking.

In a medium saucepan, melt 2 tablespoons butter over medium heat. Once melted, whisk in the flour and cook for 1 minute to eliminate the raw flour taste. Slowly add the milk, whisking constantly to avoid lumps. Add Dijon mustard, garlic powder, nutmeg, salt, and pepper. Cook, whisking often, until the sauce thickens (about 5–7 minutes).
Once thick, reduce heat to low and stir in 3/4 cup of the Parmesan cheese and all of the Gruyère if using. Stir until melted and smooth. Taste and adjust seasoning if needed.

Gently fold the blanched cauliflower into the cheese sauce until evenly coated. Pour the mixture into the prepared baking dish and smooth the top. Sprinkle with the remaining 1/4 cup Parmesan cheese.

In a small skillet, heat olive oil and butter over medium heat. Add minced garlic and cook for 30 seconds, stirring constantly to avoid burning. Add the breadcrumbs and a pinch of salt. Cook for 3–4 minutes until the crumbs are golden and fragrant. Stir in chopped parsley and remove from heat.
Sprinkle the breadcrumbs evenly over the cauliflower mixture.

Place the dish in the oven and bake uncovered for 20–25 minutes, or until bubbly and the top is golden brown. If needed, broil for the last 2–3 minutes for extra crispiness, but watch it closely.

Let rest for 5–10 minutes before serving. The sauce will thicken slightly as it cools, making for neater scoops.