* 1kg/2lb 3oz floury potatoes, such as King Edward or Maris Piper, peeled and cut into large chunks
* 250ml/9fl oz milk
* 500g/17½oz leeks, washed and cut into rounds
* 2 tbsp butter
* 1 tbsp double cream
* sea salt flakes and white pepper
Cook the potatoes in a pan of simmering water for 15-20 minutes, or until the potatoes are tender. Drain the potatoes and set aside.
In a separate pan, bring the milk to a simmer and poach the leeks for 4-5 minutes, or until tender. Drain the leeks, reserving a few tablespoons of the milk.
Mash the potatoes and fold in the butter and the cream. Add the leeks and a few tablespoons of the reserved milk and mash together until creamy. Season, to taste, with sea salt and white pepper.