In top of a stainless-steel double boiler (not yet over hot water),
beat egg yolks with an electric beater until light and fluffy.
Gradually add sugar, beating until the mixture forms
soft peaks when the beater is raised.

Place top of double boiler into bottom over just-simmering water.
Very gradually, beat in Marsala until sauce is very fluffy--about 5-7 min.
Place top of double boiler into a pan of ice water and
continue beating its contents until cool.

In medium bowl, beat cream and vanilla until soft peaks form.
Fold Marsala mixture into cream. Refrigerate until ready to serve.
Wash cherries; dry thoroughly. Set aside 6 cherries with stems;
remove stems from remaining cherries.
Refrigerate cherries and 6 large parfait or dessert dishes.

No more than one hour before serving, using a cherry pitter and
being careful to leave as small a hole as possible,
remove pits from all cherries but those with stems.
Layer cherries and zabaglione in chilled dishes,
garnishing with zabaglione and a reserved cherry.