Preparation

In a saucepan cover potatoes with cold water by 1 inch and simmer until very tender, about 45 minutes.

While potatoes are cooking, in a small saucepan heat milk and butter over moderately low heat, stirring, until butter is melted and keep warm.

In a colander drain potatoes well. Force potatoes through a ricer or medium disk of a food mill back into pan and stir in milk mixture. Fold in ricotta and salt and pepper to taste and keep potatoes warm.