In a saucepan, heat the heavy cream and whole milk over medium heat until steaming. Keep it just hot enough to steam, not boiling, so the mixture stays smooth.

In a bowl, whisk the egg yolks with the granulated sugar until thick and pale. Slowly drizzle in the steaming cream mixture while whisking constantly to prevent scrambling (visual cue: silky, uniform custard base).

Return the mixture to the saucepan and cook over medium-low heat, stirring constantly, until it reaches 175F. Watch for the custard to coat a spoon (visual cue: a clear line stays when you run a finger through).

Remove the saucepan from the heat and whisk in the creamy peanut butter until completely smooth. The custard should look glossy and evenly colored (visual cue: no peanut streaks).

Strain the custard through a fine mesh sieve into a clean bowl. This removes any tiny bits and keeps the texture silky (visual cue: very smooth flow).

Whisk in the vanilla extract and salt, then cool the custard over an ice bath until room temperature. Stir occasionally while it cools (visual cue: bowl feels cool and the custard thickens slightly).

Cover and refrigerate until cold, at least 4 hours or overnight. Chilling firms the base so it churns properly (visual cue: fully chilled, not sloshy).

Churn the chilled custard in an ice cream maker according to the manufacturer’s instructions. Stop when it reaches a soft-serve consistency (visual cue: thick, aerated, lighter texture).

Transfer to a freezer-safe container and freeze until firm. Freeze until scoopable, about a few hours, depending on your freezer (visual cue: holds shape when you open the container).