In a nonstick 1-quart saucepan, combine 3/4 cup sugar, coconut milk, and 1 cup milk. Scald mixture.
In a small mixing bowl, whisk the remaining 1/2 cup milk and cornstarch together to make a slurry. Whisk egg yolks with salt in medium bowl. Temper yolks by adding 1/2 cup scaled milk mixture to yolks and whisk well. Add yolk mixture and slurry back into milk mixture and whisk vigorously over medium heat until thickened, about 2 minutes. Remove from heat and add coconut, vanilla, and butter. Whisk until uniformly incorporated.
Pour the filling into the prepared pie shell. Cover the pie with plastic wrap and place in the refrigerator. Chill the pie completely, about 2 hours.
To serve, top with toasted coconut and a dollop of whipped cream.
Yield: 6 to 8 servings