Make the beer reduction, avoiding a boil if possible. I did this the night before over a very low heat and it took about an hour and a half.
Make custard. In a medium saucepan bring milk and sugar to a simmer. Temper the egg yolks by adding a bit of the hot milk into the eggs and combining first before adding the yolks to the milk. Cook until just thickened enough to cling to a spoon.
Place the milk chocolate in a large bowl. Pour the custard through a fine mesh strainer over the chocolate. Stir until combined.
Add the heavy cream and the vanilla and thoroughly combine.
Allow to cool for several hours or overnight until completely chilled.
Freeze in an ice cream maker according to the ice cream maker’s directions.
Put in a freezer safe container and allow to harden for several hours before scooping.
Milk Chocolate Extra Stout Ice Cream https://www.recipefiction.com/2015/03/extra-stout-ice-cream-float-with-maple-bourbon-caramel-sauce.html