Place heavy cream and milk in a heavy bottomed sauce pan over medium-low heat until it barely comes to a simmer. Look for steam and a few small bubbles.
2 cups heavy cream, 2 cups whole milk
While the milk is heating, whisk the egg yolks, sugar, and vanilla bean paste together until smooth.
3 egg yolks, ½ cup sugar, 2 tablespoons vanilla bean paste
Slowly whisk in ¼ cup of the hot milk mixture into the egg mixture. This tempers the eggs and helps prevent them from scrambling when added to the hot mixture. Then whisk the tempered egg mixture into the pot of hot milk.
Stir in a pinch of salt.
1 pinch salt
Cook over medium-low heat until the mixture begins to thicken into a custard and coats the back of a spoon. The mixture should reach a temperature between 170-180°F.
Pour custard through a fine mesh sieve into a bowl.
Place plastic wrap directly on the surface of the custard and refrigerate for at least 4 hours until fully chilled.
Churn in an automatic ice cream maker until the mixture begins to thicken. My machine takes 20-25 minutes.
Place churned ice cream in a container and place in the freezer for at least 2 hours.
Notes
Strain your custard before chilling it. Even when you carefully temper the eggs, you can still end up with small bits of egg. Straining it helps ensure your ice cream is perfectly smooth.
Make certain your custard is fully chilled (at least 4 hours) before churning.
Your churning bowl should be completely frozen before churning (at least 12 hours).
Harden ice cream in freezer after churning for at least 2 hours.
If ice cream becomes too hard, just let sit at room temperature for 10 minutes before scooping.