Heat oven to 300 degrees. In a medium bowl, whisk egg whites and salt until frothy, about 2 minutes. Stir in condensed milk and vanilla. Using a rubber spatula, fold in coconut until well combined.
Line 2 baking sheets with parchment paper or nonstick baking mats. Using a teaspoon and your fingers, form macaroons into 1 1/4-inch mounds about 1 inch apart.
Bake until macaroons are golden brown, about 20 minutes. Transfer baking sheets to a cooling rack; let cool completely. Store in an airtight container for up to a week.
You can also make Icearoon ice cream sandwiches by spooning ice cream onto the bottom of one macaroon and topping with another macaroon.