1. Put the softened butter in a basin, add icing sugar to beat
2. Add cooked egg yolk after fusion
3. Stir well until you can't see the broken egg yolk
4. Mix cornstarch, salt and low-gluten flour
5. Add it to the butter and knead it into a dough
6. Put it in a bag and refrigerate for about 1 hour
7. Knead into small balls
8. Press with your thumb
9. Put it in the oven at 170° and bake for 15 minutes
