In a medium saucepan, combine the heavy cream, whole milk, and half of the granulated sugar. Warm gently for about 5 minutes without boiling.

In a separate bowl, whisk together the unsweetened cocoa powder and remaining sugar. Gradually add the dry mixture to the warm cream, whisking until smooth.

In another bowl, whisk the egg yolks until frothy. Gradually pour about 1 cup of warm chocolate mixture into the yolks while whisking constantly.

Return the tempered yolk mixture to the saucepan. Cook over low heat, stirring constantly for 5 to 7 minutes until thickened.

Remove from heat and stir in vanilla extract and salt. Strain the custard through a fine-mesh sieve into a clean bowl.

Cover with plastic wrap and cool at room temperature. Chill in the fridge for at least 4 hours or overnight.

Pour the custard into an ice cream maker and churn according to manufacturer's instructions until soft-serve consistency.

Transfer the churned ice cream into an airtight container and freeze for at least 2 hours before serving.