Cook the pasta according to the instructions on the pack. When it is al dente, drain and leave aside.
Cut the cauliflower into florets then add to a steamer and steam for 10 minutes until it is tender.
Add the cauliflower to a blender with 500ml milk then blend until smooth and creamy.
Melt the butter in a saucepan over low heat, then whisk in the flour and stir well until it forms a roux (or paste). Whisk in the milk and blended cauliflower and stir well.
Bring to a bubble, then stir in the cheese, nutmeg, turmeric, and season with black pepper.
Divide the pasta into either one large baking dish or 2 small dishes. Equally, pour the sauce over the pasta and stir well, then sprinkle over the breadcrumbs and a little extra turmeric.
Serve the mac and cheese in bowls with a sprinkling of extra toasted breadcrumbs on top.