Combine egg whites, sugar, vanilla, melted butter, and milk in a medium mixing bowl. Whisk until smooth.
Add the salt and flour, whisk again until smooth.
Allow the batter to rest while you heat up your waffle cone iron.
Once the iron is fully preheated, spray it down with non-stick spray
Spoon on two tablespoons of batter. Shut the iron and allow it to cook until the iron indicates the cone is done.
Remove the hot waffle cone and immediately shape. Most irons use shaping tools to make a standard cone and a waffle bowl.
Hold the cone on the shaping tool for about 1 minute until it is no longer hot and hardened.
Allow the cones to rest for at least 30 minutes before scooping ice cream into them. Letting them rest and dry out will prevent the cones from getting soft and soggy.