Place Heavy Cream (1 1/2 cup) and Milk (1 1/2 cup) in a pot over medium heat.
In a bowl, whisk Egg (4) with Granulated Sugar (3/4 cup) and Salt (1 pinch) until they are fluffy and pale yellow in color.
When cream and milk mixture has gotten hot but not boiling, about 5 minutes. Whisk in Unsweetened Cocoa Powder (1/3 cup) until it is fully incorporated and then add the Semi-Sweet Chocolate Chips (1/2 cup).
Stir until chocolate chips have melted.
Add a tablespoon of hot chocolate/cream/milk mixture to the egg yolks while continuously whisking. Keep adding the hot mixture to the yolks until it is easy to pour.
Pour the egg mixture into the milk mixture and stir with a wooden spoon until it thickens and reaches 170 degrees F (75 degrees C) on a candy thermometer.
Place a strainer over a heat proof bowl.
Pour the thickened mixture through a strainer into a heat proof bowl.
Add Vanilla Extract (1 teaspoon) and chill mixture overnight, and make sure the bowl of your ice cream maker is in the freezer.
Churn the ice cream mixture according to your ice cream maker’s instructions.
After a while it should look like this. You could be done here. You could place this lovely chocolate ice cream into a freezer container and be done with it. Or you could add peanut butter.
Layer a bit of the ice cream with a bit of straight up Creamy Natural Peanut Butter (1/4 cup).
Make a few more layers. And now freeze overnight or at least five hours. You will have amazingly rich tasting and smooth textured ice cream. This will last a week in your freezer.