Pour the heavy cream into a medium bowl and set it aside.
In another medium bowl, add the egg yolks, set them aside.
In a medium pot, mix together the milk, sugar, cocoa, and salt. Heat it over medium heat for about 3 minutes, until the sugar, cocoa, and salt have dissolved.
Slowly pour about a ½ cup of the hot milk mixture into the egg yolks, whisking the eggs the whole time so they don’t scramble.
Pour the egg yolk mixture back into the pot with the rest of the milk. Cook over medium heat, stirring constantly, for about 7–10 minutes, until the mixture thickens and can coat the back of a spoon.
Place a mesh strainer over the bowl of heavy cream and pour the hot mixture through it. This helps catch any lumps. Then add the vanilla extract. Stir to combine.
To cool the mixture faster, place the bowl in an ice bath (a larger bowl filled with ice and water).
Once the mixture is cooled, cover it with a lid or plastic wrap and refrigerate for at least 2 hours.
After it’s chilled, pour the mixture into your ice cream maker and follow the instructions to churn it.
Once it’s done churning, freeze the ice cream for at least 4 hours or overnight.
Scoop into bowls or cones, add your favorite toppings, and enjoy!