Place the cauliflower florets in a saucepan with the stalk and milk and bring to the boil. Reduse the heat and simmer for 10 minutes until the cauliflower is tender.

Meanwhile, melt the butter in a frying pan and cook the leeks over medium heat, stirring occasionally, for 5 minutes.

Add the mustard and nutmeg to cauliflower, and stir in the cheese. Transfer to a food processor and whizz until smooth.

Return to the pan stir in the leeks and season with a little pepper. Heat through gently while cooking.

Heat the oil in a large frying pan over a high heat. Toss the bread cubes with the paparika and cook the croutons, stirring frequently, for 2-3 mins until golden and crisp. Drain oil on kitchen paper.

Ladle the soup into serving bowls and scatter the croutons on over the top.