Combine milk and whipping cream in top of a double boiler. Cook over boiling water, stirring constantly, until milk mixture is warm. Combine eggs and sugar in a small mixing bowl; beat well.
Gradually stir one-fourth of hot milk mixture into egg mixture; add to remaining hot milk mixture, stirring well. Cook over boiling water, stirring constantly with a metal spoon, until mixture begins to thicken and coats the spoon. Remove from heat, and stir in vanilla. Cool to room temperature; chill.
Pour custard into chilled cups, and sprinkle with nutmeg.