Heat cream, milk, sugar, and cocoa powder in a saucepan until smooth and steaming, ensuring the mixture is well combined without lumps.
Add chopped dark chocolate and stir until fully melted and incorporated into the base.
Whisk egg yolks in a separate bowl until smooth, preparing them for tempering.
Slowly add warm mixture to the yolks while whisking, then return everything to the saucepan.
Cook on low heat until thickened, stirring constantly to create a smooth custard.
Stir in vanilla and salt, strain, and chill completely before churning.
Churn in an ice cream maker and freeze until firm for the final texture.