Beat egg yolks using an electric beater until thick and lemon-colored. Place bowl over simmering water, add sugar then marsala and continue to beat until mixture resembles fluffy custard. Pour into ice cream trays, cover lightly with foil and freeze until firm, with freezer set to maximum for about 2 to 3 hours. Cover, reduce freeze to medium and allow gelato to ripen for several hours. Serves6.