Preheat the oven to 170C and line two baking sheets with baking paper.

Mix the butter and sugar in a bowl until light and creamy.

Add the egg and vanilla and mix well then stir in the flour, cocoa powder, salt and baking powder.

Mix until a dough forms. Shape the dough into a disc and wrap it in plastic wrap.

Refrigerate for 30 minutes then take small pieces of dough and shape them into balls.

Place the dough on the prepared pans and make a small indentation into each ball using your fingertip. The idea is to fill these indentations with chocolate later on.

Bake in the oven for 10-14 minutes until crisp.

Allow to cool in the pan then fill each cookie with melted white chocolate.

Decorate with chocolate shavings and matcha powder or as desired.