Mix soy sauce, mirin, dashi stock, and water together in a bowl to create the sauce base.
Add sugar and mix until dissolved.
Slice onion into thin pieces and cut chicken thigh into small nugget-sized pieces.
Divide all ingredients in half to cook one serving at a time.
Add one portion of sauce to a pan.
Add one portion of onion slices and chicken to the sauce. Cover the pan and heat on high until boiling.
Once boiling, reduce heat to a simmer. Cover the pan again and cook for 5-10 minutes, turning the chicken about halfway through.
Beat one egg and add it to the pan.
When the egg is almost fully cooked, turn off the heat and slide the cooked mixture over a bowl of rice.
Repeat steps 5-9 for the second serving.
Garnish with parsley or herb of your choice, if desired.
Enjoy!
