Step 1

Preheat oven to 240°C/475°F. Grease four 2-cup (500ml) ovenproof dishes.

Step 2

Place cauliflower on a large oven tray, drizzle with the oil and season; toss well to coat. Roast for 15 minutes or until cauliflower is almost tender and browned. Reduce oven to 200°C/400°F.

Step 3

Meanwhile, cook pasta in a large saucepan of boiling salted water for 6 minutes (or 2 minutes less than directed on the packet, see tip); drain. Return pasta to pan.

Step 4

Melt butter in a medium saucepan over medium heat, add flour; cook, stirring, until mixture bubbles and thickens. Gradually whisk in milk until smooth; cook, whisking, until mixture boils and thickens. Remove from heat; stir in mustard, cheddar and two-thirds of the parmesan until cheeses melt. Pour sauce over pasta; stir to combine.

Step 5

Spoon the pasta mixture into ovenproof dishes; press cauliflower into pasta. Combine breadcrumbs, parsley and remaining parmesan; sprinkle over pasta.

Step 6

Bake for 20 minutes or until crumbs are golden and mixture is heated through. Season to taste; serve.