Cauliflower & Seasonal Vegetables Gratin with Creamy Cheesy White Sauce

Tender roasted vegetables folded into a silky béchamel-style cheese sauce, then baked until bubbling and deeply golden on top.

Ingredients

• 1 large cauliflower (about 1–1.2kg / 2–2.5 lb), cut into medium florets
• 500g / 1 lb seasonal vegetables, cut into bite-size pieces (choose what’s in season; e.g. broccoli florets, sliced carrots, zucchini chunks, green beans)
• 2 tbsp olive oil
• 1 1/2 tsp salt, divided
• 1/2 tsp black pepper
• 4 tbsp butter
• 4 tbsp plain flour
• 3 cups (750ml) milk (any)
• 1 tsp Dijon mustard (optional but recommended; pantry staple)
• 1/4 tsp ground nutmeg (optional; pantry staple)
• 2 cups (200g) grated cheese (cheddar, gruyère, mozzarella, or a mix), divided
• 1/2 cup (50g) finely grated parmesan (optional but excellent), divided

Method

• 1

  Step 1: Roast the vegetables

  Preheat oven to **220°C / 425°F (200°C fan)**. Toss cauliflower and seasonal vegetables with **olive oil, 1 tsp salt, and pepper**. Spread on a large tray (use two trays if crowded). Roast **18–22 minutes**, tossing once halfway, until the edges are **golden** and the vegetables are **tender-crisp** (they’ll finish cooking in the bake).

• 2

  Step 2: Make the creamy white sauce (cheese béchamel)

  Reduce oven to **200°C / 390°F (180°C fan)**. In a saucepan over **medium heat**, melt **butter**. Add **flour** and cook, stirring constantly, for **1 minute** until it smells slightly **toasty** (this removes raw flour taste).

• 3

  Step 3: Season and melt in the cheese

  Stir in **Dijon** and **nutmeg** (if using), plus the remaining **1/2 tsp salt**. Turn heat to **low** and add **1 1/2 cups grated cheese** (and **1/4 cup parmesan** if using). Stir until melted and silky. Taste and adjust salt/pepper.

• 4

  Step 4: Assemble

  Tip roasted vegetables into a **baking dish** (about **2–2.5L / 2–2.5 qt**). Pour over the cheese sauce and gently toss to coat. Sprinkle with remaining **1/2 cup cheese** and remaining **parmesan**.

• 5

  Step 5: Bake until bubbling and golden

  Bake **12–15 minutes** until the edges are **bubbling** and the top is **deep golden**. If you want extra colour, broil/grill for **1–2 minutes** at the end—watch closely.

• 6

  Step 6: Rest and serve

  Rest **5 minutes** (the sauce thickens slightly). Serve hot as a main with a simple salad, or as a rich side.

Tips

• **Best seasonal veg combos:** cauliflower + broccoli + carrots; cauliflower + zucchini + green beans; cauliflower + leeks (if you have them) + carrots.
• **Sauce thickness cue:** If it gets too thick, whisk in a splash more milk. If too thin, simmer another 1–2 minutes—it thickens more in the oven.
• **Cheese choices:** Cheddar for flavour, gruyère for a nutty finish, mozzarella for stretch. A mix is ideal.
• **Make-ahead:** Roast veg and make sauce up to **2 days** ahead. Rewarm sauce gently with a splash of milk, assemble, then bake.
• **Storage:** Refrigerate leftovers **3 days**. Reheat covered at **180°C / 350°F** until hot (add a splash of milk if it looks thick).

Nutrition (per serving, estimate)