In a medium saucepan, simmer the porter until reduced by ½ in volume and set aside

In a separate saucepan, combine the cream, milk, and half the sugar. Scrape the seeds from the vanilla bean into the pan and add the bean halves. Bring the mixture to a boil over medium heat. Remove from heat.

In a medium size heat-proof bowl, whisk the egg yolks and other half of sugar. Slowly whisk part of the hot cream mixture into the egg yolks. Gradually add the egg mixture back to the hot cream. Cook over medium-low heat, stirring, until the mixture thickens enough to coat the back of a spoon and reaches 170° (about 5 minutes). Remove from heat and strain through fine mesh strainer. Add reduced porter.

Chill mixture and process in an ice cream maker according to manufacturer’s directions. When mixture begins to thicken, fold in pecans.