Put the whole chicken, onion, salt, and ground black pepper in a pan. Add water until it covers the whole chicken and boil it at medium heat. Remove the foam that forms on top during boiling to have a clear broth. Simmer until the chicken is tender. Usually, it takes about 45-50 minutes.
Remove the chicken from the pan and set aside to cool. After it is cool enough to handle, remove the skin and excess fat. Then, remove the chicken meat from the bones and tear it into strips, and set aside.
For the walnut dressing, soak the bread slices into the broth and then squeeze dry and crumble the bread into a food processor. Add crushed walnuts, garlic cloves, red pepper flakes, and ground coriander seed into the food processor. And then, combine these in a food processor to form a paste.
In a bowl, combine the walnut dressing with chicken strips. And then put the mix into a serving plate.
Put walnut oil and red pepper flakes in a frying pan and cook for about 1 minute.
Drizzle walnut oil mix evenly throughout the chicken meat mix.