In a mixing bowl, whisk together egg yolks, cornstarch, salt, and ¼ cup of milk. Set aside.
In a large pot, mix together sugar and remaining 2 ¾ cups of milk. Bring to a simmer over medium heat.
Once mixture comes to a simmer, turn off heat and pour half into the egg yolk mixture and whisk to combine well and then pour egg yolk mixture into the pot with remaining milk and sugar mixture. Stir in shredded coconut and vanilla extract until well combined.
Stir well until custard thickens.
Spoon custard into mini pie crusts, filling about ⅔ full, and spread evenly.
Place a piece of plastic wrap or parchment paper on top of custard, pressing down lightly to cover entire pie filling of each mini pie.
Place in fridge to cool and set up for 2-3 hours.