01 - Combine milk, heavy cream, and half of the sugar in a medium saucepan. Heat over medium heat until just steaming, not boiling.
02 - Whisk egg yolks with the remaining sugar and salt in a separate bowl until pale and slightly thickened.
03 - Gradually pour the hot milk mixture into the yolks, whisking constantly to temper the eggs and prevent curdling.
04 - Return the mixture to the saucepan. Cook over low heat, stirring constantly with a wooden spoon, until the custard thickens enough to coat the back of the spoon (170-175°F). Do not boil.
05 - Remove from heat and stir in vanilla extract.
06 - Pour the custard through a fine-mesh sieve into a clean bowl. Let cool to room temperature, then cover and refrigerate for at least 3 hours or overnight.
07 - Churn the chilled custard in an ice cream maker according to manufacturer's instructions until thick and creamy.
08 - Transfer to a lidded container and freeze for at least 4 hours until firm.
09 - Let sit at room temperature for a few minutes before scooping and serving.