Prepare and bake Piecrust in a 10-inch deep-dish pie plate. Cool completely on a wire rack.
To prepare filling, lightly spoon flour into a dry measuring cup; level with a knife. Combine flour, 1/2 cup sugar, salt, and eggs in a large bowl; stir well with a whisk.
Heat milk and coconut milk over medium-high heat in a small, heavy saucepan to 180° or until tiny bubbles form around edge (do not boil). Gradually add hot milk mixture to sugar mixture, stirring constantly with a whisk. Place mixture in pan; cook over medium heat until thick and bubbly (about 10 minutes), stirring constantly.
Remove from heat. Spoon custard into a bowl; place bowl in a large ice-filled bowl for 10 minutes or until custard comes to room temperature, stirring occasionally. Remove bowl from ice. Stir in extracts; spoon mixture into prepared crust. Cover and chill 8 hours or until firm.
To prepare meringue, place egg whites in a large bowl; beat with a mixer at high speed until soft peaks form. Combine 2/3 cup sugar and water in a saucepan; bring to a boil. Cook, without stirring, until candy thermometer registers 238°. Pour hot sugar syrup in a thin stream over egg whites, beating at high speed until stiff peaks form.
Spread meringue over chilled pie, and sprinkle with coconut. Broil for 1 minute or until meringue is lightly browned; cool 5 minutes on a wire rack. Serve immediately.