Marcella Hazan's mashed potatoes with milk and Parmesan cheese

Put the whole unpeeled potatoes in a pot, cover amply with water, lid on, and bring to a boil.

Boil about 40 minutes, checking tenderness with a fork without puncturing them too much or they waterlog.

Drain and peel while still hot.

Set up a double boiler, a saucepan of water coming to a simmer with a bowl above it that the water does not touch.

Put the butter in the top bowl and mash the potatoes through the food mill directly onto it.

Heat the milk in a small saucepan until nearly boiling.

Add the milk two to three tablespoons at a time, mixing with a fork or a whisk.

Once half the milk is in, beat in the Parmesan cheese, then resume with the milk.

Keep beating, taking as much milk as the potatoes will absorb before becoming thin and runny, until they are a soft fluffy mass.

Add salt to taste and a tiny grating of whole nutmeg, and serve at once.