Sabayon, which is the French version of zabaglione, is a foamy Italian custard made by whisking together egg yolks, wine, and sugar over simmering water.
Combine sugar and yolks in the top of a double boiler, beating with a mixer at medium speed until foamy. Add wine and water. Cook over simmering water until mixture reaches 160° (about 7 minutes), beating with a mixer at medium speed. Serve immediately over peaches. Garnish with fresh mint sprigs, if desired.