Execution
Follow the master commands
1
Preheat the oven to 200C/400F/Gas 6 (180C fan).
2
Put the potatoes into a saucepan of cold salted water. Bring up to the boil and simmer until completely tender. Drain well and then mash with the butter and milk. Add pepper and taste to check the seasoning. Add salt and more pepper if necessary.
3
For the fish filling, melt the butter in a saucepan, add the leeks and stir over the heat. Cover with a lid and simmer gently for 10 minutes, or until soft. Measure the flour into a small bowl. Add the wine and whisk together until smooth.
