Step 1

Add the blue pea flower and vinegar to 80 gr of warm water. Let them sit for 15 minutes. Use the back of the spoon to lightly mash the flower. Squeeze out any liquid from the flowers and you have the blue color liquid now

Step 2

I use a store-bought red bean paste and roll the paste into about 50 gr balls. Set aside

Step 3

If you plan to use egg yolk, you need a smaller ball, about 30-35 gr. Roll into balls. Flatten with your palm to about 4-inch circle. Place one salted egg yolk in the middle and wrap the bean paste around it. Continue with the rest

Step 4

Add sugar to the warm blue liquid.  In a large mixing bowl, rub the shortening into the flour. It will feel crumbly. Gradually add the blue liquid and continue to mix and knead until you form a non-sticky dough. Cover and let it rest for 30 minutes

Step 5

Rub the shortening into the flour until it forms a smooth dough. Cover and let the dough rest for 30 minutes

Step 6

Give both dough a few kneads and they should be smooth now. Divide the water dough and oil dough each into 6 equal portions

Step 7

Keeping the rest covered, take one oil dough and one water dough. Flatten the water dough and place one oil dough in the middle

Step 8

Wrap the water dough around the oil dough. So the oil dough is nested inside the water dough now. Repeat with the rest of the doughs

Step 9

Use a rolling pin to roll this dough into a flat oval shape

Step 10

Roll it up tightly starting from the bottom like a Swiss roll

Step 11

Turn the dough vertical and roll it out again

Step 12

Now you have a long flat strip of dough. Roll it as thin as you can as it will give you more spiral in the finished products later

Step 13

Roll it up tightly again starting from the bottom into a Swiss roll

Step 14

Cut this into half

Step 15

Here is how the cut-side looks like (all those beautiful spirals are right here after baking!). Keep them covered tightly and rest for another 30 minutes before rolling them out

Step 16

Work with one at a time, flip the cut side down and use a rolling pin to roll it out into a circle, about 7-inch in width

Step 17

Place the filling in the middle

Step 18

Gather the sides to wrap the filling. Pinch to seal at the bottom. When you flip it over, this is how it looks like. Place them on a baking sheet lined with parchment paper

Step 19

Repeat with the rest of the doughs. Preheat your oven to 350 degrees while you are halfway through working with the dough

Step 20

Place the baking sheet, 3rd rack from the top into the oven and bake for about 20-25 minutes or until the bottom is golden brown. Remove from the oven and let them cool on the baking sheets for 5 minutes and then remove to cooling rack to let them cool down completely