Preheat the oven to 350°F (175°C). Spread the coconut evenly on a baking sheet. Toast for about 5 minutes, stirring occasionally, until golden brown.
In a medium saucepan, whisk together half-and-half, eggs, sugar, flour, and salt. Cook over low heat, stirring constantly, until the mixture thickens and begins to boil.
Remove from heat. Stir in ¾ cup toasted coconut and vanilla extract, reserving the remaining coconut for garnish.
Pour the custard filling into the pre-baked pie shell. Smooth the top with a spatula.
Refrigerate for at least 4 hours until firm and set.
Just before serving, spread whipped topping over the pie and sprinkle with the reserved toasted coconut.