1Preheat oven to 350.
Grease 2 baking sheets.
Combine the condensed milk, key lime juice and flour in a medium bowl.
2Stir in the grated coconut and then the sugar.
If using sweetened coconut, taste the mixture before adding the sugar.
Add the sugar only if you think it is necessary.
The cookie should have a tangy flavor from the key lime juice.
3Drop teaspoons of the mixture onto a baking sheet, leaving 2 inches between each cookie; they will spread while baking.
Bake for 25 minutes until they just start to turn golden.
Remove from the pan to a rack to cool.
Store in an airtight container.
NOTE from CinStraw:
I use my cookie sheet with the cavaties-slots in it so the cookies can't run together. And I don't have to grease it.