Spray the frying pan with low calorie cooking spray and saute the leeks over a medium heat for 4-5 minutes until soft.
Add the cabbage to the pan, stir well then add the stock and mustard powder.
Turn the heat down to low, cover with a tight fitting lid and allow to steam. After 5 minutes, stir, replace the lid and continue cooking for a further 5 minutes.
Stir in the cream cheese and allow a minute or two to warm through.
Season with black pepper and serve.