How to Make It
In a medium saucepan, combine the wine, sugar, vanilla bean with seeds and 1 tarragon sprig and bring just to a boil. Add the peach halves and simmer over moderate heat, turning occasionally, until tender, about 10 minutes. Let cool completely, then refrigerate until chilled, at least 1 hour.
In a medium bowl, whisk the sour cream with a big pinch of salt. Dollop the cream in bowls and top with the peach halves and some of their poaching liquid. Garnish each plate with a tarragon sprig and serve.