Whisk eggs, sugar, salt, and vanilla*, until sugar is completely dissolved. Add milk and mix to combine.
*First, cut off the straight end of the vanilla bean. Then place the tip of your knife below the curled end and cut the vanilla bean through the middle of the bean lengthwise with a sharp knife. Although you don't need to cut it all the way through, it's ok when you do so. Then open the vanilla bean and scrape out the flavorful seeds with the back of your knife. Just use the seeds.