Place the chocolate pieces in a large bowl and set a strainer on top. Combine the milk, sugar, salt and coffee beans in a medium saucepan and place over medium heat. Once the mixture is warm, cover, remove from heat and allow to steep for 1 hour.

Uncover and rewarm the coffee mixture. Meanwhile, whisk together the egg yolks in a medium bowl. Slowly pour the warm milk mixture into the egg yolks, whisking constantly. Pour the entire mixture back into the saucepan and place over medium heat. Stir constantly with a heatproof spatula until the mixture is thick enough to coat the spatula. Pour the custard through the strainer over the chocolate and press on the beans to extract as much flavor as possible. Discard the beans and stir until the chocolate has melted. Once the mixture is smooth, whisk in the cream, stout and vanilla.

Place over an ice bath and stir until cool, then refrigerate until completely chilled before freezing in an ice cream maker according to manufacturer’s instructions.