Add water to the heavy-bottomed saucepan, cover with a tight-fitting lid and bring it to a boil.

Once boiling, turn off the heat and remove the pot from the stove.

Add 200ml cold water to the pot of just-boiled water and stir.

Gently submerge the cold eggs, one at a time, into the hot water using a skimmer.

Immediately cover with the lid and set a timer for 17–20 minutes depending on your preferred firmness of the egg yolk.

Combine dashi, mirin, soy sauce, and dried bonito flakes in a small saucepan and bring it to a boil. Once boiling, turn off the heat.

Strain the sauce through a sieve and set aside.

After 17–20 minutes, gently take the eggs out of the water. Set them aside for 5 minutes.

Cut the green onion into thin slices and set aside.

Crack the egg into a small bowl, pour the sauce and add green onion garnish as you like.