150-250ml milk or UHT cream, or a combination, heated
salt and pepper to taste
Wash the potatoes and place in a saucepan with enough water to cover them, add a teaspoon salt to the water. Bring to boil and lower heat to simmer until tender (easily pierced with a fork). Drain potatoes, peel and mash to the desired texture while hot.
Place the mashed potatoes in a saucepan over low heat for 2-3 minutes to let them dry out, stirring now and then. Remove from heat.
Warm the milk or cream without boiling - add the butter and seasoning to the milk, if you like. Then add the hot liquid to the mash, a little at a time, mashing it in, or stir with a wire whisk, until smooth.
For a silky texture, pass the mash through a fine sieve with the help of a pastry scraper while it is still hot.