Traditionally Oyakodon is cooked per serving in a donburi pan, which makes it easier to slide on top of the rice. You can replicate this by using a small frying pan and halving the ingredients OR cook the whole thing in a larger frying pan and spoon out the mixture. This recipe will cook two servings in a larger pan.
Prepare rice - see notes for a link to a blog post about cooking Japanese rice.
Slice the chicken thighs into small bite sized pieces and marinate them in the cooking sake and salt.
Cut the onion into slices (vertically) and set aside.
Place the kimchi into a small mixing bowl and chop up into smaller pieces using scissors. Add in the gochujang and mix well.
Combine the dashi, mirin, sugar and soy sauce and set aside.
Prepare the eggs by cracking them into a small jug and gently pop the yolks. You don't want to fully combine the egg as Oyakodon typically has a marble pattern made from the different parts of the egg.
In your frying pan, add a small amount of neutral oil and fry the kimchi/gochujang mixture for 2-3 minutes, or until the mixture is slightly thicker. Make sure to keep mixing so it doesn't burn.
Once the kimchi mixture has cooked a bit, add in the onion and dashi stock. Simmer on a medium heat for 10 minutes or until the onions are semi-translucent.
Once the onions are done, add in the chicken thigh and arrange evenly around the pan. Cook on a medium heat for about 3-4 minutes, or until halfway cooked. Flip the chicken an cook the other side for the same amount of time.
One the chicken is cooked, turn down the heat and gently pour over the egg mixture. Cover with a lid and cook for about 2 minutes. Traditionally the egg is not cooked for long and is very soft, this results in a creamier dish. If you prefer well done eggs, cook for longer.
Just before your eggs are done, add in the grated cheddar and mozzarella and cover for about 30 seconds, or until the cheese has melted.
Serve the rice in a bowl and crown it with the topping, garnish with sliced spring onion and enjoy!