Preheat your oven to 350°F (175°C) and line a baking sheet with a silicone baking mat or parchment paper.
In a mixing bowl, combine the powdered sugar and flour.
Add the melted butter, egg whites, vanilla extract, and a pinch of salt to the dry ingredients. Mix until you have a smooth batter.
Using a spoon, carefully place small dollops of the batter onto the prepared baking sheet, leaving enough space between them.
Use an offset spatula to gently spread and shape each dollop of batter into thin, lace-like circles. Be creative, creating irregular shapes to resemble coral.
Bake in the preheated oven for 5-7 minutes, or until the edges turn golden brown.
Remove the tuiles from the oven and let them cool for a minute before carefully transferring them to a wire rack to cool completely. They will become crisp as they cool.