Add all ingredients except cooking oil together and set aside to marinate while you prepare the other ingredients.

When ready to cook, heat pan, and add cooking oil.

Brown chicken on both sides, then remove from pan and set aside.

In the same pan, toast chilli padi, shallots, garlic, lemongrass, and galangal until lightly browned.

Add chicken stock and bring to boil, then add lime leaves and coriander root.

Cover, reduce heat to medium and allow to infuse for 5 minutes.

Then fish out and discard lemongrass, shallot, garlic, lime leaves, coriander root, and galangal.

Add musrooms, tomato, cai xin stems, and prawn.

Allow to cook for a minute.

Season with fish sauce, sugar, and lime juice.

Add in cai xin leaves, and give it a quick stir.

Thicken gravy with corn starch slurry.

While stirring, pour in beaten egg.

Remove from heat, and stir in reserved chicken pieces.

Serve over steamed rice, garnish with coriander.