Mix well 90 grams icing sugar and 125 grams butter. If caster sugar is not available, add about 125 grams of granulated sugar.
Add the eggs one by one. Mix.
Add 100 grams of flour and also the baking and vanilla powder. Mix again.
Then first add about 200 grams of wheat starch, mix. Then add remaining 200 grams of starch slowly and mix. Stop adding starch when your dough is ready.
You should obtain a soft and non-stick dough.
Without waiting make small, walnut sized buns and place them on an oven tray. Make sure they do not touch each other as they will rise. Either use an oven sheet or spread some liquid oil such as corn oil on the tray so the cookies do not stick on the bottom.
Cook about 10-15 minutes in a pre-heated oven at 170° Celsius. After 5 minutes reduce the heat to 150° Celsius. Take the tray out of the oven when the cookies slightly change color.