Use a potato peeler to pare off the skins as thinly as possible and then cut the potatoes into even-sized chunks, not too small. If they are large, quarter them and if they are small, halve them.
Put the potato chunks in a large saucepan then pour boiling water over them, add 1 dessertspoon of salt, put on a lid and simmer gently until they are absolutely tender – they should take approximately 25 minutes.
The way to tell whether they are ready is to pierce them with a skewer in the thickest part; the potato should not be hard in the centre. And you need to be careful here, because if they are slightly underdone you do get lumps!
Meanwhile melt 1 oz (25 g) butter in a large frying pan and saute the cabbage for about 3 minutes, keeping it on the move until it's tender and slightly golden at the edges then add the chopped spring onions and continue to cook for another minute.
Next drain the potatoes, return them to the pan, cover with a clean tea-cloth and leave them aside for 2 minutes to allow the cloth to absorb the excess steam.
Now, using potato masher mash until smooth, add the nutmeg, cream and remaining butter then mix thoroughly before tasting and seasoning.
Then finally stir in the contents of the frying pan and serve with or without extra melted butter.