1. Preheat oven to 425°.
2. Fit dough into a 9-inch pie plate coated with cooking spray. Fold edges under; flute. Line dough with foil; arrange pie weights or dried beans on foil. Bake at 425° for 10 minutes; remove weights and foil, and bake an additional 10 minutes or until golden. Cool completely on a wire rack.
3. Combine milk and half-and-half in a medium saucepan over medium heat. Add 1 1/2 cups coconut. Scrape seeds from vanilla bean; stir seeds and pod into milk mixture. Bring milk mixture to a simmer; immediately remove from heat. Cover and let stand 15 minutes. Strain through a cheesecloth-lined sieve into a bowl. Gather edges of cheesecloth; squeeze over bowl to release moisture. Discard solids.
4. Combine 2/3 cup sugar, cornstarch, salt, and egg yolks in a large bowl, stirring with a whisk. Gradually add milk mixture to egg yolk mixture, stirring constantly. Return milk mixture to pan; bring to a boil, whisking constantly. Remove from heat. Add butter; whisk until smooth. Place pan in a large ice-filled bowl for 6 minutes, stirring to cool. Pour into prepared crust. Cover and chill at least 1 hour.
5. Place 3 egg whites and cream of tartar in a large bowl; beat with a mixer at high speed until soft peaks form. Combine 1/2 cup sugar and 1/4 cup water in a saucepan; bring to a boil. Cook, without stirring, until candy thermometer registers 250°. Pour hot sugar syrup in a thin stream over egg whites, beating at high speed until thick. Spread meringue over pie. Cover and refrigerate at least 2 hours. Top with toasted coconut before serving.