Chop all the ingredients for the curry paste into small enough pieces for your blender to handle. Put in the blender with enough water to blend into a paste. Don’t worry about adding too much water; you can always cook it off later. Traditional Ayam Kapitan has largish pieces of chopped onions to give a pearl-like appearance, which many Malaysians feel is necessary for Ayam Kapitan to be authentic. My children, however, do not like to see their onions, so I put them in with the curry paste ingredients in the blender. You can do either without much difference in taste.
Heat the oil in a large skillet or wok. A cast iron dutch oven works really well for this too. Cook the onions till soft if you haven’t blended them.
Lower the heat to medium, and add the curry paste to the hot oil (and onions if they’re there) and cook it for about 5 minutes, stirring frequently.
Add the chicken and cook until it turns white on the outside.
Add the coconut milk and bring it to a boil on high heat for about 5 minutes.
Simmer on low heat until the chicken is tender and cooked through.
Add salt, sweetener, and lemon or lime juice. Stir and turn off the heat. Leave the lid half on for about 5 minutes to let the flavors set.
Serve with cauliflower rice or konjac rice or noodles for a THM S/keto meal. For a THM crossover, serve with rice and/or potatoes.