How to Make It
Whisk together sugar and flour in a medium saucepan. Whisk together half-and-half and egg yolks in a bowl; whisk into sugar mixture. Cook over medium, whisking constantly, until mixture thickens and starts to bubble, 8 to 10 minutes. Remove from heat. Add 1 1/2 cups of the coconut and 3 tablespoons of the butter; stir in vanilla. Transfer mixture to a medium bowl. Place plastic wrap directly on warm custard to prevent a film from forming; chill 4 to 24 hours.
Process cookies in a food processor until very finely chopped, about 1 minute. Add remaining 6 tablespoons butter; pulse until combined, about 5 times. Press mixture into bottom and up sides of a 9-inch pie plate. Chill at least 30 minutes or up to 24 hours.
Beat 1 cup of the heavy cream with an electric mixer on medium-high speed until stiff peaks form, about 2 minutes. Fold into chilled coconut custard. Spoon into prepared pie shell, and smooth top.
Preheat oven to 350°F. Spread remaining 1 1/2 cups coconut on a rimmed baking sheet. Bake until golden brown, about 12 minutes, stirring twice during bake time. Set aside.
Microwave caramel candies and remaining 2 tablespoons heavy cream in a medium-size microwavable bowl on HIGH until melted, about 2 minutes, stirring every 30 seconds. Top pie with toasted coconut around the edges (leaving center open), and drizzle with melted caramel and chocolate. Chill at least 30 minutes or up to 24 hours.