Preheat the oven to 350ºF. Line two baking sheets with parchment paper and set them aside.

Fill a large skillet about halfway with water and bring it to a simmer over medium heat.

In a heatproof bowl, combine the egg whites, sweetened coconut, sugar, vanilla, and salt. Place the bowl on top of the skillet so the bottom of the bowl does not touch the water (double boiler).

Cook the mixture over the simmering water, stirring frequently, until it thickens and becomes opaque, about 5 minutes.

Remove the bowl from the skillet and let the mixture cool until warm or near room temperature, about 30 minutes.

Using about 2 tablespoons of the mixture for each macaroon (a medium cookie scoop works well), scoop mounds onto the prepared baking sheets, spacing them about 2 inches apart.

Bake at 350ºF for about 5 minutes.

Without removing the baking sheets from the oven, reduce the oven temperature to 325ºF and continue baking the macaroons until they are lightly browned with some darker edges, 10–15 more minutes.

Remove the baking sheets from the oven and let the macaroons cool on the sheets for a few minutes, then transfer them to a wire rack to cool completely.