Place peaches into large bowl. In a small bowl, mix sugar and flour; pour this over peaches and stir gently until evenly distributed. Pour into pie shell. Dot with butter.

Note: Make vanilla sugar 2 weeks ahead: Scrape the seeds of 1 vanilla bean into 2 cups sugar and stir them in. Store sugar in a tightly closed jar, along with the buried vanilla pod. For a shortcut: Whiz ½ cup sugar in a coffee grinder with the seeds scraped from ¼ vanilla bean and use right away.