01 - In a small bowl, combine dashi stock, soy sauce, mirin, sake, and sugar. Stir until the sugar dissolves completely.
02 - Heat a medium skillet over medium heat. Add the sliced onion and sauce mixture. Simmer for 3–4 minutes until the onion softens and becomes translucent.
03 - Add the chicken pieces to the pan. Cover and simmer for 6–8 minutes, turning halfway through, until the chicken is cooked through and no longer pink.
04 - Lightly beat the eggs in a bowl. Pour eggs evenly over the chicken and onion mixture. Cover and cook for 1–2 minutes until the eggs are just set but still slightly runny. Remove from heat immediately to prevent overcooking.
05 - Divide the hot rice between two bowls. Gently slide the chicken and egg mixture over the rice, maintaining the fluffy egg texture.
06 - Garnish with sliced spring onions. Serve immediately while hot for the best texture and flavor.