Peel the bitter orange. Cut the peels into thin slices and soak them in water to remove some of their bitterness.
Squeeze the bitter orange’s juice from a fully peeled fruit.
Squeeze the juice from two limes to yield approximately two tablespoons.
In a mixing bowl, combine the lime juice and bitter orange juice.
Add the fermented shrimp paste (kapi) and dissolve it in the citrus juices. Continue to stir until the smell of the kapi has faded and mellowed.
Add the dried shrimp powder.
Taste and finalize seasoning the salty element seasoning to a sour-salty flavor profile. Add salt and fish sauce gradually because the base saltiness of the kapi you are using might vary.
Add palm sugar, and season to a desired sour-sweet-salty or sour-salty-sweet flavor profile.
Add the sliced garlic and sliced shallots.
Add the sliced yellow chilies. Reserve some for the garnish.
Serve and garnish with the rest of the chilies and the sliced and washed bitter orange peel.