Preheat the oven to 350°F (177°C). Line two large baking sheets with parchment paper or silicone baking mats and set aside.
Pulse the coconut in a food processor 8 to 10 times to break it up a little.
Add the coconut, flour, and salt to a large mixing bowl and mix until well combined. Add the sweetened condensed milk and pure vanilla extract and continue mixing until fully combined.
Using a 1.5 tablespoon cookie, scoop the mixture onto the prepared baking sheets.
With damp hands, form each macaroon into a round ball.
Bake for 12 to 15 minutes or until the bottoms of the macaroons are lightly browned and they are set.
Remove from the oven and allow to cool for 10 minutes on the baking sheets, then transfer to a wire rack to cool completely.
Line a separate large baking sheet with parchment paper.
Once the macaroons have cooled, add the chopped chocolate to a microwave-safe bowl. Microwave in 20 to 30 second increments, stirring well after each increment, until completely melted and smooth.
Dip the bottoms of each macaroon into the melted chocolate, allowing any excess chocolate to drip off, and place onto the prepared baking sheet. Drizzle any excess chocolate over the top of the macaroons, then refrigerate for 30 minutes or until the chocolate has hardened.