In a medium bowl, whisk the egg yolks, granulated sugar, cornstarch, and salt together and set aside.
In a saucepan, heat the milk and 1/2 cup heavy cream over medium low heat until it begins steaming and small bubbles form around the sides. Do not bring to a boil!
Once heated, slowly pour 1 cup of the milk/cream into the egg mixture to temper the eggs. Do this slowly while whisking the whole time to ensure the eggs do not scramble.
Pour the tempered egg mixture into the saucepan with the rest of the milk and cream.
Heat your custard on medium low 1-2 minutes until it has thickened. Remove from heat and stir in the vanilla extract.
Pour the custard into a bowl and line it with plastic wrap. Refrigerate at least 2 hours and up to 2 days. It will continue to thicken as it chills.
While your custard is chilling, heat your oven to 400F and blind bake your pie crust 12-14 minutes.