Heat oven to 325° F. Line 2 baking sheets with parchment.
Whisk the eggs white, vanilla, salt, and cream of tartar in a large bowl with an electric mixer on medium-high until soft peaks form, 2 to 3 minutes. With the machine running slowly add the sugar until dissolved and stiff peaks form, 1 to 2 minutes. Fold in the coconut, stirring until evenly combined.
Using a small ice cream scoop, drop the batter in mounds (about 1 tablespoons each) 1 inch apart on the prepared baking sheets. Bake, rotating the sheets halfway through, until golden brown, 26 to 30 minutes; let cool completely. The macaroons will keep for up to 5 days at room temperature in an airtight container.