1 14-ounce package sweetened shredded coconut (about 5 cups)
4 large egg whites
2/3 cups sugar
1/3 cup all-purpose flour, spooned and leveled
1/4 teaspoon kosher salt
1/2 teaspoon pure vanilla extract
6 ounces bittersweet or semisweet chocolate, melted and cooled to room temperature
Heat oven to 325° F.
In a medium bowl, combine the coconut, egg whites, sugar, flour, salt, and vanilla. Drop packed tablespoonfuls of the mixture onto parchment-lined baking sheets, spacing them 1 inch apart.
Bake, rotating the baking sheets halfway through, until lightly golden, 25 to 30 minutes. Cool slightly on the baking sheets, then transfer to wire racks to cool completely.
When cool, dip the bottom of each macaroon into melted chocolate and place on a parchment-lined baking sheet. Refrigerate until firm, about 20 to 30 minutes. Store the macaroons in an airtight container at room temperature for up to 7 days.