In a cold fry pan, add the oil and the sugar. Turn the heat up to medium high and allow the sugar to slowly caramelise.
Once the sugar has started to form bubbles and is amber in colour, take off the heat and allow it to go a little further without burning. Then add the chicken, put the pan on low-medium heat and stir the chicken around to coat in the caramel for about 3 minutes.
In a small bowl, combine the chicken bouillon or stock powder (if using) with 1/4 cup of boiling water. Stir the mixture into the fry pan with the garlic, ginger, salt, sugar and pepper.
Turn down the heat to medium and put the lid on the fry pan with about 3 cm (1 in) gap for the steam to escape. Cook for 6 minutes.
After 6 minutes, flip the chicken to colour the other side. Cook for a further 6 minutes partially covered.
Check if the chicken is cooked. If yes, add the fish sauce and onion wedges and stir. Cook for a further 2 minutes uncovered to take the edge off the onions. If no, cook the chicken until done then add the fish sauce and onions.
Check the seasoning of your sauce and adjust according to your taste. (Note 1)
Garnish with chopped spring onions and serve with white jasmine rice.