In a medium pan off the heat, add the coconut milk, whole milk, ½ cup of sugar, coconut flakes, and salt. Whisk well. Bring to a simmer over medium high heat, stirring occasionally.
1 13.5 oz can coconut milk, 2 cups whole milk, 1 cup sugar, ¾ cup coconut, ½ teaspoon kosher salt
In a medium bowl, whisk together the remaining ½ cup sugar, egg yolks, and cornstarch.
8 egg yolks, 6 tablespoon cornstarch
Whisk 1 cup of the simmering milk mixture in the yolks, pouring it in very slowly and whisking constantly. Then slowly whisk the tempered egg mixture into the rest of the milk mixture on the stove.
Cook on medium heat, whisking vigorously, until it is thick and few bubbles pop on the surface, about 1-2 minutes.
Remove from the heat. Add the vanilla and cold butter, and mix often until it is warm, about 5-8 minutes.
3 tablespoon butter, 2 teaspoon vanilla
Pour into the cooled crust, cover with plastic wrap on the surface, and chill in fridge for 4-6 hours.