To begin, prepare the base of the dish by whisking together the dashi, soy sauce, mirin, sugar, and sake in a medium sized bowl. This sauce will provide the umami rich flavour of the Oyakodon. Make sure the sugar dissolves completely to achieve a smooth sauce. Set aside.

Next, slice the onion into thin pieces. This will help it cook quickly and blend smoothly with the chicken and eggs. Set aside the onion while you prepare the chicken.

In a separate bowl, beat the eggs lightly, making sure not to overbeat them. The eggs should have a light, uniform consistency but should still contain visible streaks of white and yolk. This technique helps retain a delicate texture when cooked.

In a large skillet or donburi pan (shallow Japanese pan), heat the prepared sauce over medium heat. Once it begins to simmer, add the sliced onions and cook for 3-4 minutes until they soften and turn translucent. Stir occasionally to ensure even cooking.

Add the chicken pieces to the simmering onion and sauce mixture. Spread them evenly across the pan, making sure each piece is coated in the flavourful sauce. Cook the chicken for about 6-7 minutes, or until fully cooked through. The chicken should be tender and absorb the rich flavors of the sauce.

Once the chicken is cooked, lower the heat to medium-low. Slowly pour the beaten eggs over the chicken and onion mixture. Pour in a circular motion to ensure even distribution of the egg. Cover the pan with a lid and let the eggs cook for 2-3 minutes, or until they are just set but still slightly runny.

While the egg is cooking, prepare your serving bowls by placing a generous amount of hot, steamed rice into each one. The rice will act as the base for the Oyakodon, absorbing the savoury flavors from the chicken and egg.

To serve, gently spoon the chicken and egg mixture over the rice, making sure to include the flavourful sauce from the pan. Garnish with freshly chopped green onions for a burst of freshness and a sprinkle of shichimi togarashi or chili flakes for a touch of spice, if desired. Enjoy your Oyakodon warm, savouring the harmony of the tender chicken, soft eggs, and perfectly seasoned broth atop a bed of rice.