Mince the rakkyo pickles, add the beaten egg, shiro-dashi, and vinegar and mix together well.
Heat oil a little more than usual in a tamagoyaki pan on medium heat and add half of the mixture from Step 1. Cook it until it is like a half-cooked scrambled egg, stir it and gather it at the far end of the pan.
Lower the heat and add the rest of Step 1. Pour it in so it gets under the egg you cooked first. Let it sit and cook for 1 minute while paying attention to the strength of the heat.
Roll it once. When it's half-cooked and crumbly, don't worry. Use a spatula to gently roll it again.
Form it into a rectangle. Continue cooking on low heat while keeping an eye on it.
Flip it once again, arrange it into a rectangle, and thoroughly cook it on low heat.
When it has finished cooking, let it cool completely on top of a paper towel.
This was an experiment with rakkyo pickles. I minced rakkyo pickles and rolled them in a tamagoyaki and it turned out sweet and so tasty, so I uploaded the recipe.
When your tamagoyaki has a lot of filling, take your time, don't rush, and patiently form the shape. In the summer, it'll be a food safety hazard if the tamagoyaki is half-cooked, so make sure to thoroughly cook it on low heat.