In a medium saucepan, combine cream, milk, and cocoa powder.

Simmer, whisking to combine.

Remove from heat and add chocolate chips.

Whisk until melted.

In a medium mixing bowl, whisk together the sugar and egg yolks for a couple of minutes until they turn pale.

Add 1/2 cup of the milk mixture to the egg mixture, whisking to temper the eggs (so they don't cook).

Repeat 3-4 more times, 1/2 cup at a time, then return this mixture to the saucepan and stir to combine with the remaining milk mixture.

Add FINE chopped pistachios, return the saucepan to low-medium heat, and bring back just to a simmer.

Simmer and stir a couple of minutes or until the mixture thickens slightly and will coat the back of a spoon.

Remove pan from heat.

Pour the mixture through a sieve into a bowl, pressing through the sieve with a rubber spatula to save as much of the liquid as possible.

Place this bowl in an ice bath for a few minutes to stop the cooking process, then cover the bowl and refrigerate for several hours, until completely cooled.

Freeze the ice cream in your ice cream maker according to your maker's directions.

In the last few minutes of freezing (when you've reached soft serve consistency), add the 1/2 cup chopped pistachios and allow to mix in.

Enjoy ice cream now for soft serve, or freeze overnight in a freezable container for a harder/scoopable consistency.