How to Make It
In a large soup pot, cook the pork over moderate heat, turning frequently, until it begins to brown and some of the fat is rendered, about 5 minutes. Add the butter and annatto and cook, stirring, until the butter is melted. Stir in the onion, cover and cook over low heat until softened, about 5 minutes. Add the water and bring to a boil. Add half of the callaloo, cover and cook until just barely wilted. Add the remaining callaloo, cover and cook until fully wilted, about 5 minutes longer. Discard the salt pork, season with salt and pepper and serve.