Place the butter, sugar, vanilla, baking powder, and salt in the mixer.
Beat until a paste forms.
Add 1 egg and beat until it is absorbed.
Transfer to a plate.
Add the flour and mix with hand until just combined.
Keep the dough in the refrigerator for an hour to chill so that you can easily shape them.
When ready to bake, preheat the oven to 180ºC.
Line a baking tray with baking paper or silicon baking mat.
Take small lime size portion of the dough, roll in between your palm, press a little to flatten and place in the baking sheet.
Make the egg white wash by beating the egg white with 1 tablespoon of water until foamy.
Brush the top of each cookie with the egg white wash.
Bake in the oven for 10 minutes or until the edges are just barely brown.
Let cool on the baking sheet for 10 minutes before moving to a wire cooling rack.
For the Chocolate frosting melt 1/2 cup of white chocolate chips in microwave or double broiler method.
Add some food colour and mix.
Pour this slightly cool melted chocolate over the cool cookies.
Sprinkle some colourful sugar balls or simply granulated sugar.
Let the chocolate set completely and serve.
