2. Beat the butter until it is creamy, then add salt, and beat the sugar 2-3 times while beating until it turns white. Add egg yolks one by one and mix well. Then pour in the flour and mix it gently with a rubber shovel.
3. Knead 2 into a ball of 2 ~ 3cm, roll it in the egg white solution, drain the excess egg white with two spoons, roll it on the broken walnut kernel, and put it on the baking tray after being covered with the walnut kernel powder.
4. press a pit in the center of the ball with your thumb and put in a proper amount of jam. Bake in the oven for 15~2 minutes.