Place a mesh strainer over a bowl and set aside.

In a medium saucepan, combine the heavy cream with cocoa; bring to a boil over medium-high heat.

Remove the cream mixture from the heat and add chopped chocolate; stir until the chocolate has melted and the mixture is smooth.

Add the milk and sugar and cook over medium-low heat, stirring, until the mixture is hot.

In a bowl, whisk the egg yolks with the salt. Whisk in about 1 cup of the hot cream and milk mixture. Return the egg yolk mixture to the saucepan and cook, stirring, until the custard reaches 175 F to 180 F or until it coats the back of a spoon.**

Pour the custard through the strainer into the bowl.

Cover the bowl with plastic wrap and let it stand until it reaches room temperature, then refrigerate for about 2 hours, or until thoroughly chilled. The custard may be made the day before and refrigerated overnight. Alternatively, for faster chilling, set the bowl inside a larger bowl of ice and water and stir frequently, then place it in the fridge until chilled.

Pour the chilled custard into an ice cream maker and churn following the manufacturer's directions.

Spoon the ice cream into a container, alternating with layers of marshmallows, toasted nuts, and chocolate chips. Swirl to distribute the ingredients evenly.

Cover the container and freeze until firm.