Add the granulated sugar, table salt, and cornstarch to a large bowl and whisk to combine.
Add the egg yolks, milk, and light cream to the mixture and whisk until well combined.
Place a saucepan over medium-low heat and pour the custard mix into the pot.
Cook the mixture for 10-12 minutes (or until thickened), whisking continuously to keep the mixture from scalding. *Mix until the custard is thick enough to coat the back of a spoon.
Remove the pan from the heat, then add the butter and vanilla extract. Stir to combine.
Pour the custard into a medium bowl and cover by placing a piece of plastic wrap directly on the surface of the custard, leaving no space between the plastic and custard. This prevents a skin from forming.
Refrigerate the custard for 3-4 hours (overnight is best) before serving.
