Toast ½ cup of the shredded coconut in a dry skillet over medium-low heat, stirring frequently, until golden. Remove from heat and cool.
¾ cup shredded sweetened coconut
In a medium bowl, whisk egg yolks, cornstarch, and ¼ cup milk. Set aside.
4 large egg yolks, ¼ cup corn starch, 1 ¼ cups whole milk
In a saucepan, combine remaining 1 cup milk, coconut milk, sugar, salt, and toasted coconut. Bring to a simmer, stirring occasionally.
14 ounceS unsweetened coconut milk, ⅔ cup granulated sugar, ¼ teaspoon salt
Gradually whisk a ladleful of the hot mixture into the yolk mixture to temper, then slowly pour it all back into the saucepan.
Cook over medium heat, whisking constantly, until thickened (about 2–3 minutes). Remove from heat and stir in butter, vanilla, and coconut extract.
2 Tablespoons unsalted butter, 1 teaspoon vanilla extract, ½ teaspoon coconut extract
Pour filling into the baked crust. Place plastic wrap directly on the surface to prevent a skin from forming. Chill at least 4 hours or overnight.