1. Boil the blueberries into jam ahead of time, soften the butter in advance, beat with a whisk, add in powdered sugar in portions, and beat evenly
2. Beat the eggs in three to four times and add them in three to four times, and add another time after beating each time until they are completely beaten.
3. After the egg mixture is evenly beaten, add a little vanilla extract and continue beating
4. Sift the high-gluten flour and add it to the butter paste and mix thoroughly. Take the corresponding cookie mouthpiece and put it into the piping bag
5. Put the biscuit paste into the piping bag and squeeze it into the baking tray one by one
6. Take a bowl of water and dip a little water with chopsticks, press lightly in the middle of the squeezed biscuits (the water is outside the material), and squeeze the prepared blueberry jam into the middle of the biscuits (the recessed part)
7. Preheat the oven in advance, set the temperature to 175 degrees, top and bottom fire, put the baking tray into the middle layer, and take about 20-25 minutes to cool down.