1. Place ricotta in a cheesecloth-lined sieve set over a bowl. Place in refrigerator, and drain overnight.

2. Combine milk and nutmeg in a medium saucepan; bring to a simmer.

3. Combine egg yolks and sugar in the bowl of an electric mixer fitted with the paddle attachment. Cream at medium-high speed until very thick and pale yellow, 3 to 5 minutes. Return the milk to a simmer.

4. Add half of the warm milk to egg-yolk mixture; whisk until blended. Return new mixture to saucepan with remaining milk. Cook over low heat, stirring constantly, until mixture is thick enough to coat the back of a wooden spoon.

5. Have ready an ice-water bath. Remove saucepan from heat, and immediately stir in cream. Pass mixture through a sieve set over a medium bowl. Place bowl in ice-water bath, and chill. Whisk in drained ricotta until thoroughly blended.

6. Freeze in an ice-cream maker according to manufacturer's instructions. Store in an airtight container.