Dashiwaki Sandwich

Split the egg into a bowl and loosen it well with chopsticks. Add sugar and kelp stock and mix well.

Soak salad oil into a paper towel, blend it with the oil into a frying pan for egg yaki and place it on the heat. Pour in 1/4 of the egg mixture and spread it all over, and when the whole thing is getting a little hard, wrap it from the back towards the front. Once it's close to the front, add oil again and move the eggs to the back of the frying pan.

Pour in 1/3 of the remaining egg mixture, and once it has solidified, roll it towards the front. The remaining egg mixture is also wrapped up.

Remove the egg rolled into the cutting board and slice it into the top and bottom half. Cut off any protruding parts on the left and right to suit the size of the bread.

Spread melted butter and mustard on the sandwich bread, and sandwich the spoon rolled egg from [4]. Cut it into a size that's easy to eat and it's finished.