01 - Combine dashi stock, soy sauce, mirin, sake, and sugar in a small bowl. Stir thoroughly until sugar completely dissolves.
02 - Heat a medium skillet over medium heat. Add sliced onions and pour in the prepared sauce mixture. Simmer for 3-4 minutes until onions become tender and translucent.
03 - Add chicken pieces to the skillet. Cover and simmer for 6-8 minutes, turning pieces halfway through cooking, until chicken is fully cooked and tender.
04 - Lightly beat eggs in a bowl. Pour evenly over the chicken and onion mixture. Cover and cook for 1-2 minutes until eggs are just set but still slightly creamy. Remove from heat immediately to prevent overcooking.
05 - Divide hot steamed rice between two serving bowls. Gently slide the chicken and egg mixture over the rice, ensuring sauce is distributed evenly.
06 - Sprinkle finely sliced spring onions over the top. Serve immediately while eggs remain silky and sauce is hot.