Onsen egg sous vide

I wish I had a picture that could capture the flavor. A perfect custardy egg in a dashi-mirin-soy sauce. Made at home, consistently. What else can one desire?

A sous vide circulator is in my opinion a perfect device for two things. One is slow cooking meat at low temperature for a long time. Short ribs, pork belly, shanks, any meat cut where gelatine comes in play. A pressure cooker does an amazing job in a fraction of time, but if one has the time and can plan ahead, nothing beats sous vide. The second amazing application is cooking eggs as described in the amazing record of an egg-cooking experiment done by the one and only J. Kenji López-Alt. I shamelessly use that article as my definite reference when it comes to eggs and sous-vide, and overall, his sous-vide explorations are a source of inspiration. If you have an Instant Pot with a sous vide setting, you can have onsen eggs for breakfast - set it up in the evening, on a timer, and enjoy in the morning. 

Ingredients:

• Eggs
• For kaeshi sauce:
• 4 parts of Soy sauce
• 1 part Mirin
• 1 part Sugar
• Dashi - remember a simple way to make dashi in a fridge
• Use between 10 to 3 parts of dashi per 1 part of kaeshi

Method:

• Cook eggs in a 145F degree water bath for 1.5 hours.
• Note: Use a mesh basket or a bowl to hold eggs in place. They may crack if they are pushed around by the flow of water. You can put eggs in the water immediately as you fill the pot, no need to wait for the water to come to temperature. You can also cook them for longer than 1.5h, I've definitely gone beyond 2h and it was OK.
• In a pot, mix mirin and soy sauce at the ratio of 4 parts of soy sauce to 1 part of mirin. Set aside one part of sugar.
• Note: Find a good soy sauce. It makes a big difference.
• Also measure dashi, you will need 10 parts of dashi to 1 part of soy-mirin mixture.
• Note, you can vary greatly how much dashi to use. It really depends on your mood an preferences. Serving eggs cold calls for a saltier mixture, I have heard of even 3:1 ration of dashi to kaeshi sauce, but that is too salty for me.
• Bring soy-mirin mixture to a boil to let alcohol evaporate.
• Dissolve sugar into soy-mirin mixture. You just made kaeshi sauce.
• Add dashi and warm up.
• One can debate whether you should boil the mixture. I sense no major difference in taste if I do, but purists or people with more sensitive palate may disagree.
• Crack an egg into a small helper bowl.
• Gently remove the egg with a spoon, leaving the non-solidified whites behind.
• Put the egg into a serving bowl, and carefully pour some sauce around the egg.
• Serve, eat, and be amazed.

These eggs are very versatile and don't have to be just served in dashi-soy sauce. One can use them in place of poached eggs, or for example in a shakshuka to avoid overcooking that can happen so easily.