1. Prepare ingredients
2. After the butter is softened, add sugar and beat until fluffy and white
3. Add the delicate egg yolk and mix well
4. Sift in cake powder, milk powder, milk, and liquid egg yolk
5. Knead evenly in the plastic wrap, divide them into small balls of the same size, flatten them, and place them in a baking tray
6. Fire up and down at 160 degrees for 25 minutes, the surface will be slightly yellow
7. Out of the oven
