1. Preheat oven to 170C degree. Combine eggwhites and sugar well in a bowl. Add melted butter, vanilla, salt, coffee powder (optional) and sifted flour. Mix well with a whisk until smooth in texture.
2. Add the flaked almonds and mix to combine evenly with a spatula.
3. Spread the mixture evenly using your wet finger on the prepared sheets of an oven tray ( parchment paper or baking paper works too). Alternatively you can spoon a tablespoon of the almond mixture and spread into a circle thinly using your wet a finger.
4. Bake at 170C degree for about 10 to 12 mins or until lightly golden.
5. Remove from the oven and let it cool to room temperature. Break the tuile as you desire.