Cook the rice according to package instructions.
Preheat the oven to 400. Cut the chicken breast in half, width wise, so you have two flat pieces of chicken.
Next let's toast the panko. Add 1 tbsp olive oil to a pan over medium heat. Add panko and stir. Continue to stir and cook until panko is toasted and golden brown. Take off the heat.
Transfer the panko to a shallow bowl or plate. Add flour to another bowl, and 1 egg to another. Whisk the egg using a fork or whisk.
Dip one piece of chicken in the flour, coating both sides. Shake off any extra flour then transfer the chicken to the egg bowl. Cover both sides in egg then transfer the the panko bowl. Once the chicken is coated in panko, transfer it to a baking sheet. Repeat with the remaining piece of chicken.
Drizzle the chicken with a bit of olive oil then transfer to the oven. Bake at 400 for 15 minutes, or until the temperature of the chicken has reached 165 degrees. Cut the chicken into small strips and set aside.
To a bowl add 2 cups of water, dashi stock, soy sauce, rice vinegar, and sugar. Whisk until combined.
Chop the onion into thin strips. Add half of the onions to a small pan with a drizzle of olive oil. After two minutes add half of the dashi stock mixture. Cook for 2 more minutes until the onions are mostly cooked.
Carefully place one of the cooked chicken cutlets onto the top of the onions and broth. Whisk an egg in a small bowl and pour the egg over the chicken and onions. Cover the pan for 2 minutes to let the egg cook.
Scoop half the rice into a bowl. Carefully transfer the chicken and onion mixture over the rice. There will be extra sauce that pours over the rice as well.
Repeat with the remaining onions and chicken. If you have the space, you can prepare both chicken cutlets simultaneously in two pans.
Top with chopped green onions and enjoy!