Cut large fruits into 1/2-inch-thick slices. Halve and pit cherries. Divide among 4 serving dishes or cups.
Whisk together egg yolks and sugar in a large nonreactive stainless steel bowl. Set bowl over a pan of simmering water (water should be about 2 inches below bowl). Pour in Muscat, and whisk vigorously to incorporate air until mixture has more than doubled in volume, is lightly frothy, and is as thick as softly whipped cream, about 3 minutes. If yolks begin to cook at sides of bowl, continue to whisk while lifting the bowl about 3 to 4 inches above the simmering water.
Spoon sabayon over fruit, making sure not to scrape up any cooked egg from sides, and serve immediately.
This recipe calls for Muscat de Beaumes-de-Venise wine. This is available from GothamWines.com, 212-932-0990.