Take the vanilla ice cream out of the freezer for 10 minutes or so to soften. Once barely softened, add to the blender 4 scoops of vanilla ice cream, the milk, chocolate syrup, and the chilled stout, pouring slowly so as not to generate lots of beer foam.
Add the pinch of salt and blend to a smooth consistency. For a thicker consistency, add more vanilla ice cream.
Pour the milkshake into 4 glasses and float 1 mini pretzel on top of each glass.
