Preheat your oven to 250 degrees Fahrenheit. Line two baking sheets with parchment paper.
In a large bowl, whisk together the granulated sugar and light corn syrup until well combined. Add in the cornstarch.
Beat the egg whites on high speed using an electric mixer or stand mixer until soft peaks form (about 5 minutes).
Gradually add half of the whipped egg white mixture into the sugar and syrup, stirring constantly. Once combined, fold in the remaining egg whites along with butter extract/vanilla.
Gently fold in one-third cup at a time until no dry ingredients show (this step ensures lightness). Spoon dollops of batter onto prepared baking sheets and spread into small circles, about 1.5 inches wide using the backside of a spoon or offset icing tool.
Bake in preheated oven for approximately 8 minutes until they are golden brown but still slightly undercooked (they will harden as they cool). Remove from baking sheets and transfer to wire racks. Allow them to completely dry, which could take upwards of an hour.
Once fully dried or set, roll in unsweetened flaked coconut until evenly covered.