Let pie crust stand according to package directions. Unroll pie crust; place into a 9-inch pie plate. Tuck pie crust under and flute edges. Do not prick pie crust. Line pastry with double thickness of foil.
Bake in a 450 degrees F oven for 8 minutes. Remove foil. Bake for 4 to 6 minutes more or until crust is light brown. Remove from oven. Cool on a wire rack. Reduce oven temperature to 350 degrees F.
In medium saucepan, melt butter over medium-low heat. Stir in sugar and flour. Remove from heat; set aside.
In a medium bowl, beat eggs lightly with a whisk until combined. Add buttermilk and vanilla; whisk until just combined. Gradually whisk buttermilk mixture into butter mixture until smooth. Stir in coconut.
Place partially baked pastry shell on the oven rack. Carefully pour filling into shell. Cover edge of pie with foil to prevent overbrowning.
Bake in the 350 degree F oven for 30 minutes. Remove the foil; bake pie about 10 minutes more or until a knife inserted near center comes out clean. Cool slightly on a wire rack. Serve warm. Cover and store any remaining pie in the refrigerator within 2 hours. Let chilled pie stand at room temperature for 1 hour before serving. Makes 8 servings.