This is a riff on colcannon – an Irish dish of mashed spuds and cabbage – but with no cabbage in sight. Add as much butter as you dare.
900g (about 2 lbs) floury potatoes (good for mashing)
Bunch spring onions (scallions)
50g (1-2 oz) butter
2 Tbsp chopped parsley
150ml (about 5 fl oz) whole milk
1 Peel potatoes and cut into cubes. Steam or cook gently in salted water until tender. Remove potatoes still in their steamer and set them on a rack so air can circulate underneath, or alternatively, drain potatoes into a large sieve. Cover potatoes with paper towels and leave to dry off for a few minutes.
2 Meanwhile, trim and chop spring onions. Transfer to a small saucepan with half the butter. Cover pan with a lid and cook gently until tender; be careful not to let them fry.
3 Transfer potatoes to a large warmed bowl. Mash with a potato masher, adding salt to taste – you’ll be surprised how much it takes to bring out the full flavour (as much as 1½ tsp salt!), and stir in spring onions and all the buttery juices, and the parsley. Beat in enough hot milk to form a creamy purée and taste for seasoning. Transfer to a warmed serving bowl, whip a spoon through the top to make a few hollows and dot with remaining butter. Serve immediately.