Preheat oven to 450F. Line 9" pie plate with pastry. Trim and flute edges; do NOT prick pastry. With rotary beater, beat flour, sugar and sour cream (use commercial sour cream from store). Arrange flat edge of peach quarters on pastry in concentric circles. Pour sour cream on top. Bake 15 minutes at 450F, then lower heat to 350F and bake 25-30 minutes or till filling is set. Sprinkle brown sugar over hot pie. Broil 1-2 minutes till sugar is melted. Serve warm.