Step 1 : Break the cauliflower into flowerettes and cook in boiling salted water for 15 minutes.

Step 2 : Drain and put into a warm ovenproof dish.

Step 3 : Makes a sauce by melting the butter, stirring in the flour to form a dry roux, and finally adding the milk.

Step 4 : When thick, remove from the heat and stir in the egg yolk, mustard and yoghurt.

Step 5 : Add the chopped bacon.

Step 6 : Pour over the cauliflower, sprinkle with breadcrumbs and paprika, and brown under the grill.