Bring the milk to a simmer in a saucepan over moderate heat.
Meanwhile, whisk together the egg yolks and sugar until smooth. Add a
little of the hot milk to the egg yolk mixture, then whisk the egg
mixture into the milk.
Cook, stirring constantly, until the mixture
has thickened slightly, about 15 minutes. Do not boil. Refrigerate
the custard until well chilled, at least 1 hour.
Meanwhile, combine
the rhubarb and sugar in a saucepan over low heat and cook covered for
25 to 30 minutes, stirring frequently. Strain and discard the liquid.
Mash the rhubarb with a fork and chill.
Prior to serving, fold the
whipped cream into the custard, and then fold in the rhubarb. Serve
in stemmed wine glasses or parfait glasses.
