• In a wok, mix dashi, sake, soy sauce, and sugar. Bring to a boil, then maintain a strong boil.
  
• Add the onion and the white parts of the green onions. Cook for about 5 minutes until half tender.
  
• Add the chicken. Cook while stirring until fully cooked and the broth is reduced by half, 5 to 7 minutes for thigh meat or 3 to 4 minutes for breast meat.
  
• Incorporate half of the green onions and the mitsuba. Adjust the taste with more soy sauce or sugar if necessary.
  
• Reduce the heat to a gentle simmer. Pour the beaten eggs and whites in a thin stream, using chopsticks to distribute.
  
• Cover and cook the eggs to your liking, 1 minute for runny eggs or 3 minutes for medium-firm.
  

To serve

• Put the hot rice in a large bowl or individual bowls.
• Add the egg and chicken mixture with the excess broth.
• Add an egg yolk to the center of each bowl.
• Garnish with the remaining green onions and togarashi.