Preheat the oven to 170°C (340°F), top and bottom heat. Line a baking tray with parchment paper.
Lightly whisk the egg white until slightly frothy.
Rub the sugar and lemon zest together, then mix with the vanilla, salt, and egg white.
Add the shredded coconut and all-purpose flour, then mix until a soft, slightly sticky dough forms.
Chill the dough for 15–20 minutes.
Shape 8–9 balls (about 20–22 g each) and roll them in the shredded coconut.
Place them on the prepared baking tray and bake for 14–16 minutes, until the tops are lightly golden.
Let the cookies cool completely on the baking tray. If desired, sprinkle a few toasted coconut flakes over the cookies before serving.