1. Peel the potatoes, wash them, slice them, and steam them in a pot
2. Take it out and pour it into a larger container, press it into a puree, add the egg yolk puree and mix evenly
3. Add butter and mix evenly
4. Add milk powder and mix well
5. Add pure milk and mix well
6. Add flour and cornstarch
7. Just stir evenly
8. Put your favorite piping mouth into the piping bag, and put the mixed cookie paste
9. Line a baking tray with greased paper, squeeze in the cookie paste, and preheat the oven at 200 degrees for about 10 minutes
10. Put it in the middle of the preheated oven and bake at 180 degrees for 20 minutes.
The temperature of the oven is determined by the nature of the oven. It is best not to leave the person at the first baking, and pay attention to the changes of the cookies to avoid burning.