Peaches with Sabayon

1/4 cup sugar
3 large egg yolks
1/4 cup Marsala
2 tablespoons water
8 cups sliced, peeled peaches (about 4 pounds)

Combine sugar and yolks in top of double boiler. Beat with mixer at medium speed until foamy.
Add water and wine. Cook over simmering water until misture reaches 160 degrees (about 7 minutes) beating with a mixer at medium speed.
Serve immediately over peaches.