Quick Recipe Version (TL;DR)
Quick Ingredients
- 1 large head cauliflower (2 to 2.5 lb / 900 g–1.1 kg), cut into florets
- Kosher salt, black pepper
- 4 tbsp (56 g) unsalted butter
- 1/4 cup (30 g) all-purpose flour
- 3 cups (720 ml) whole milk, warm
- 2 tsp Dijon mustard + 1/2 tsp dry mustard powder
- 8 oz (225 g) sharp cheddar, grated
- 1 oz (30 g) Parmesan, grated (optional)
- 1/4 tsp ground nutmeg
- 1 cup (50 g) panko breadcrumbs
- 2 tbsp (28 g) unsalted butter, melted
- 1 oz (30 g) sharp cheddar, grated (for topping)
- 1 tbsp chopped chives or parsley
Do This
- 1. Heat oven to 425°F (220°C). Butter a 2–2.5 qt (2–2.5 L) baking dish.
- 2. Boil cauliflower in well-salted water for 5 minutes; drain and steam-dry 5 minutes.
- 3. Melt 4 tbsp butter; whisk in flour 1 minute. Gradually whisk in warm milk; simmer 5–7 minutes until thick.
- 4. Off heat, whisk in Dijon, mustard powder, nutmeg, 3/4 tsp salt, pepper. Stir in 8 oz cheddar + Parmesan until smooth.
- 5. Combine cauliflower with sauce; transfer to dish.
- 6. Toss panko with 2 tbsp melted butter and 1 oz cheddar; sprinkle on top. Bake 20–25 minutes until bronzed and bubbling. Rest 5 minutes; garnish with chives.
Why You’ll Love This Recipe
- Velvety cheddar-mustard béchamel that clings to every floret.
- Golden, buttery breadcrumb lid for irresistible crunch.
- Balanced sharpness from Dijon and a whisper of nutmeg.
- Weeknight-easy with simple steps and make-ahead options.
Grocery List
- Produce: 1 large head cauliflower, fresh chives or parsley
- Dairy: Whole milk, sharp cheddar, Parmesan (optional), unsalted butter
- Pantry: All-purpose flour, panko breadcrumbs, Dijon mustard, dry mustard powder, ground nutmeg, kosher salt, black pepper
Full Ingredients
Cauliflower
- 1 large head cauliflower (2 to 2.5 lb / 900 g–1.1 kg), cut into 1.5-inch florets
- 1 tbsp kosher salt (for blanching water)
Cheddar-Mustard Béchamel
- 4 tbsp (56 g) unsalted butter
- 1/4 cup (30 g) all-purpose flour
- 3 cups (720 ml) whole milk, warmed
- 2 tsp Dijon mustard
- 1/2 tsp dry mustard powder
- 8 oz (225 g) sharp cheddar, coarsely grated
- 1 oz (30 g) Parmesan, finely grated (optional)
- 3/4 tsp kosher salt, plus more to taste
- 1/2 tsp freshly ground black pepper
- 1/4 tsp ground nutmeg
Buttery Breadcrumb Topping
- 1 cup (50 g) panko breadcrumbs
- 2 tbsp (28 g) unsalted butter, melted
- 1 oz (30 g) sharp cheddar, grated
To Finish
- 1 tbsp chopped chives or parsley
- Flaky sea salt and extra black pepper, to serve (optional)
Step-by-Step Instructions
Step 1: Heat the oven and prep the dish
Preheat the oven to 425°F (220°C). Lightly butter a 2–2.5 quart (2–2.5 L) baking dish, such as a 9-inch square or medium oval casserole. Warm the milk in a small saucepan or in the microwave until steaming but not boiling; warm milk blends more smoothly into the roux.
Step 2: Blanch and steam-dry the cauliflower
Bring a large pot of water to a boil and salt it generously (about 1 tbsp kosher salt). Add the cauliflower florets and boil for 5 minutes until just tender but still holding their shape. Drain thoroughly, then spread on a towel-lined sheet pan to steam-dry for 5 minutes. This prevents a watery sauce later.
Step 3: Make a smooth roux
In a medium saucepan over medium heat, melt 4 tbsp (56 g) butter. Sprinkle in the flour and whisk constantly for 1 minute to cook off the raw taste; do not let it brown. You should have a smooth, paste-like roux.
Step 4: Build and season the béchamel, then add cheese
Gradually whisk the warm milk into the roux, a splash at a time at first, until smooth. Bring to a gentle simmer, whisking, and cook 5–7 minutes until thick enough to coat the back of a spoon. Remove from heat. Whisk in Dijon, dry mustard, nutmeg, 3/4 tsp kosher salt, and black pepper. Stir in 8 oz (225 g) cheddar and the Parmesan (if using) until fully melted and glossy. Taste and adjust salt or pepper.
Step 5: Combine florets and sauce
Add the drained, steam-dried cauliflower to a large bowl. Pour the hot cheese sauce over the top and fold gently with a spatula to coat every floret without breaking them. Transfer to the prepared baking dish, spreading into an even layer.
Step 6: Mix the crunchy topping
In a small bowl, toss the panko with 2 tbsp melted butter until evenly moistened. Stir in the remaining 1 oz (30 g) grated cheddar. Sprinkle the mixture evenly over the sauced cauliflower.
Step 7: Bake until bronzed and bubbling, rest, and serve
Bake at 425°F (220°C) for 20–25 minutes until the edges are bubbling and the topping is a deep golden brown. If needed, broil for 1–2 minutes for extra color, watching closely. Let rest 5 minutes to set. Scatter with chopped chives or parsley and finish with a pinch of flaky salt and a few grinds of pepper before serving.
Pro Tips
- Steam-dry the florets after blanching so the sauce stays thick and silky.
- Warm milk helps prevent lumps and speeds up thickening of the béchamel.
- Take the sauce off heat before adding cheese to avoid a grainy texture.
- Use freshly grated cheddar for superior melt and flavor; pre-shredded often contains anti-caking agents.
- For extra crunch, mix 1 tsp olive oil into the breadcrumbs and broil briefly at the end.
Variations
- Bacon and Leek: Sauté 4 oz (115 g) diced bacon until crisp; remove. In the fat, soften 1 thinly sliced leek (light green parts) for 5–6 minutes. Fold both into the sauce with the cauliflower.
- Broccoli-Romanesco Mix: Swap half the cauliflower for broccoli or Romanesco; blanch the firmer florets 1 minute longer.
- Gluten-Free: Use a 1:1 gluten-free flour blend for the roux and gluten-free panko.
Storage & Make-Ahead
Refrigerate leftovers in an airtight container for up to 3 days; reheat covered at 350°F (175°C) for 15–20 minutes, then uncover to re-crisp. Make-ahead: Blanch cauliflower and make sauce up to 2 days ahead; store separately and assemble just before baking. Or assemble fully (without baking), cover, and refrigerate up to 24 hours; bake straight from the fridge, adding 5–10 minutes. Freezing (assembled, unbaked) is possible for up to 2 months, though the sauce may separate slightly; bake from frozen at 375°F (190°C) covered for 35–40 minutes, then uncover 10–15 minutes to brown.
Nutrition (per serving)
Approximate for 6 side servings: 440 calories; 20 g protein; 33 g fat; 22 g carbohydrates; 3 g fiber; 720 mg sodium.
