Start by placing the mackerel fillets in a large saucepan filled with water and 1 teaspoon of pink salt and bring to the boil.
Boil the mackerel for about 5-10 minutes.
After the given time, drain the fish off (you can use a colander to do so) then leave to completely cool.
Use a fork or your hands to flake the fish in a medium sized bowl then set aside.
Pour the coconut milk into a medium sized frying pan on medium heat.
Add the onion, scallion, garlic, bell peppers, tomatoes, pimento berries, thyme and all purpose seasoning and stir.
Leave to simmer for 10-15 minutes (it may take alittle longer so be patient), stirring occasionally, during the given time the coconut milk should thicken and start to reduce.
Once the coconut milk has thickened, fold in the flaked mackerel.
Continue to cook until there is very little coconut milk left (you may need to increase the heat to help evaporate the coconut milk).
Do a taste test and add additional black pepper and pink salt to taste.
Remove the thyme stems before serving.