I found this recipe on allrecipes.com. Good depth of chocolate flavor without being overly sweet.The description on the original recipe said "This is a very rich, custard style chocolate ice cream."
Combine sugar, milk, salt and cocoa powder in a saucepan over medium heat, stirring constantly. Bring to a simmer. Place the egg yolks into a small bowl. Gradually stir in about 1/2 cup of the hot liquid and return to saucepan.
Heat until thickened but do not boil. Remove from the heat and stir in the chopped chocolate until chocolate is melted. Pour into a chilled bowl and refrigerate for about two hours until cold, stirring occasionally.
When chocolate mixture has completely cooled, stir in the cream, and vanilla extract. Pour into an ice cream maker and freeze according to manufacturer's directions.