Place an oven rack in the middle position. Preheat the oven to 350 degrees F. Line a large baking sheet with parchment paper.
Combine the flour, coconut and salt in a bowl. Add the condensed milk (make sure you get all of it) and vanilla. Mix until a very thick coconut mixture forms. Lightly dampen your hands with cold water, and then roll the coconut mixture into 2" balls (don’t make them perfect looking) and place on the baking sheet, spacing them about 2" apart. Bake 20 minutes, until light golden. Cool on a rack, then store in an airtight container at room temperature for up to 2 weeks.