Tres leches mashed potatoes

Peel the potatoes with long strokes running from top to bottom, dropping them into a bowl of water as they are done.

Quarter the potatoes: halve them down the centre, then turn each half flat side down and cut it in half.

Put the potatoes in a big pot, cover by an inch or two of water, salt generously with at least a couple of tablespoons of salt and bring to a boil on high heat.

Stir once at the boil and not again, then reduce to between low and medium-low and keep a gentle simmer until very tender.

Combine 1/2 cup evaporated milk, 1/2 cup milk and a little buttermilk in a saucepan and keep hot on very low heat without boiling or reducing.

Test with the tip of a thin knife: it should slide in with no effort without the potato falling apart.

Drain very well, transfer to a big bowl and mash with a wire potato masher for about half a minute before adding anything.

Add the butter in slices and mash about half a minute more until it disappears.

Season with a little more salt, white pepper and three shakes of cayenne.

Add the hot milk mixture, holding back a tablespoon or so, and whip with a hand mixer on high until light and fluffy.

Taste for salt and texture; add the reserved milk if needed and whip once more.

Transfer to a serving bowl, make ridges with the edge of a spoon, drizzle with melted butter and finish with snipped chives.