In a large bowl combine flour, baking powder, and salt. Using a pastry blender or two knives, cut in butter until mixture resembles coarse cornmeal. Stir in sour cream and milk until just combined. Cover and chill 30 minutes or up to 2 days.
Preheat oven to 450 degrees F. For two 7-inch pies, divide dough in half. On a lightly floured work surface, roll to two 8 1/2-inch circles. transfer to two 7-inch pie tins. (For a 9-inch pie do not divide dough, roll to an 11-inch circle, and transfer to a 9-inch pie plate). Trim crusts even with top of pie tins. With a lightly floured fork, press sides of crust into pie plate. Line with a double thickness of foil that has been coated with nonstick cooking spray to prevent pastry from sticking. Bake 8 minutes. Remove foil; bake 5 to 6 minutes more or until crust is golden; cool. Reduce oven to 350 degrees F.
Cut peaches into thick slices, slicing around the pit. Add peaches to cooled crusts. Cover edges of pies with foil.
Bake 20 to 25 minutes, or until peaches are just tender. Transfer to a rack. While pies are still warm, drizzle with 1/4 cup of the Butterscotch Sauce. Serve immediately (crust becomes soggy as pie sits) with ice cream. Sprinkle with nutmeg and fresh mint. Pass remaining warm Butterscotch Sauce. Makes 6 to 8 servings.
In a small saucepan melt unsalted butter over medium heat. Stir in brown sugar and light-colored corn syrup. Bring to a boil and boil gently, uncovered, for 5 minutes, stirring frequently. Carefully stir in whipping cream. Cool slightly. Serve immediately. Makes 1/2 cup.