Ingredients:
- 1 large head cauliflower (about 2 lbs / 900g), cut into bite-sized florets
- 2 Tbsp olive oil
- 1/2 tsp fine sea salt
- 1/4 tsp freshly ground black pepper
- 4 Tbsp unsalted butter, cubed
- 4 Tbsp all-purpose flour
- 2 1/2 cups whole milk, warmed
- 1 tsp Dijon mustard
- Pinch of ground nutmeg
- 6 oz (1 1/2 cups) sharp Cheddar cheese, grated
- 4 oz (1 cup) Gruyère cheese, grated
- 1/2 cup Panko breadcrumbs
- 1/4 cup finely grated Parmesan cheese
- 1 Tbsp melted butter
Instructions:
- Preheat oven to 400°F (200°C). Toss cauliflower florets with olive oil, salt, and pepper on a large roasting tray. Roast for 20–25 minutes until tender and lightly golden brown at the edges. Set aside.
- Make the Roux: In a medium heavy-bottomed saucepan over medium heat, melt the butter. Whisk in the flour continuously for 1–2 minutes until a smooth paste (the roux) forms and smells slightly nutty. Do not let it brown.
- Form the Béchamel: Gradually whisk in the warmed milk, ensuring no lumps form. Bring the sauce to a gentle simmer, whisking frequently, until it thickens enough to coat the back of a spoon (about 5–7 minutes).
- Create the Mornay Sauce: Remove the pan from the heat. Stir in the Dijon mustard and nutmeg. Add the grated Cheddar and Gruyère in handfuls, stirring until completely melted and smooth before adding the next batch. Taste and adjust seasoning with salt and pepper.
- Assemble the Bake: Lightly grease a 9x13 inch baking dish. Fold the roasted cauliflower florets gently into the cheese sauce until coated. Transfer the mixture to the prepared dish.
- Prepare the Topping: In a small bowl, toss the Panko breadcrumbs, Parmesan, and melted butter together until evenly coated. Sprinkle evenly over the cauliflower mixture.
- Bake & Finish: Bake for 15 minutes until the sauce is bubbling hot. For the final touch, switch the oven to the grill (broiler) setting for 2–3 minutes, watching closely, until the topping is gloriously golden brown and crisp. Let it rest for 5 minutes before serving.