Bring milk to a simmer. Meanwhile, combine egg yolks and sugar in the bowl of an electric mixer. Beat at medium-high speed until very thick and pale yellow, 3 to 5 minutes.
Add half the milk to egg-yolk mixture, and whisk until blended. Stir into remaining milk, and cook over low heat, stirring constantly, until mixture is thick enough to coat a spoon.
Remove from heat, and immediately stir in cream. Pass mixture through a strainer into a medium mixing bowl set in an ice bath. Whisk in melted chocolate, and let chill, then freeze in an ice-cream maker according to manufacturer's instructions. Store in an airtight plastic container in the freezer.
This did not turn out well...directions are a bit complicated, and when I added the melted chocolate at the end, it got grainy and never "smoothed-out." Also, how long am I supposed to cook the custard before it coats the spoon? After 30 mins, nothing, but I just kept going with the recipe.