Preheat the oven to 350 degrees F (175 degrees C). Spread coconut on a baking sheet.
Bake in the preheated oven, stirring occasionally, until golden brown, about 5 minutes.
Combine half-and-half, sugar, flour, eggs, and salt in a medium pot. Bring to a boil over low heat, stirring constantly, until mixture thickens and coats the back of a wooden spoon, about 15 minutes.
Remove the pan from the heat and stir in 3/4 cup toasted coconut and vanilla; reserve remaining toasted coconut for garnishing the pie.
Pour custard into pie shell and chill until firm, about 4 hours.
Top with whipped topping and reserved toasted coconut.
