3/4 cup sweet wine, such as Muscat de Beaumes-de-Venise, at room temperature
1 teaspoon finely grated orange zest
2 cups mixed fresh berries
Mint sprigs, for garnish
Pour 2 inches of water into a saucepan and bring to a boil. Prepare an ice water bath in a medium bowl. Place 4 large wineglasses in the freezer to chill.
Crack the egg yolks into a large stainless steel bowl. Add the sugar and whisk until pale and slightly thickened, about 2 minutes. Add the wine and orange zest. Set the bowl over the boiling water and whisk constantly over moderately low heat until the sabayon is thick and has doubled in volume, about 8 minutes. Immediately set the bowl in the ice water bath and let cool, stirring occasionally, about 15 minutes.
Spoon the cold sabayon into the chilled wineglasses and top with the mixed berries. Garnish the sabayon with the mint sprigs and serve.