Peel and slice peaches, place into large bowl. In a separate bowl, combine cornstarch and 2 to 3 tablespoons sugar. Add remaining sugar, eggs and buttermilk. Mix well. Stir in ½ cup melted butter and vanilla. Pour over peaches. Stir until peaches are coated. Pour filling into unbaked pie crust. Moisten pastry edge with water.
Cover pie with top crust. Cut slits or designs in top crust to allow steam to escape.
For glaze, brush with 2 tablespoons melted butter. Sprinkle with sugar. Bake at 400 degrees F for 45 minutes or until filling in center is bubbly and crust is golden brown. Cool to room temperature before serving. Refrigerate leftover pie.