To remove skin from peaches, submerge into boiling water for 30 seconds, then transfer to ice bath for another 30 seconds. Skin should easily peel off.
Peel and slice peaches, set aside.
In large sauce pan, heat brown sugar in white wine until melted. Reduce heat so that your mixture is just under boiling.
Split vanilla bean and scrape out those wonderful black seeds. Add all the seeds and the split bean to the wine and sugar mixture. Wipe any remaining seeds stuck to your fingers on the peach slices. You don't want to waste a spec.
Add the peaches to the wine, sugar and vanilla mixture, cover, and poach for 15 minutes.
Remove peach slices with slotted spoon. Increase heat to bring liquid to a gentle boil and cook uncovered for 10-15 minutes or until liquid is reduced by half.
Serve peaches with syrup warm, room temperature, or cool. Top with mascarpone and garnish with fresh mint, if desired. Use to top crepes, ice cream, or enjoy on their own.