Heat the wine and sugar in a pan over a gentle heat. Add the peach halves and poach for 8-10 minutes.
For the sabayon, whisk the egg yolks, wine, sugar and vanilla seeds in a bowl over a pan of simmer water for up to 10 minutes, until pale, thickened and fluffy and the mixture leaves a ribbon trail.
Remove the peaches from the liquor and transfer to a serving plate. Spoon a little of the sabayon on top and drizzle a little liquor over, to serve.