Cut the gizzards in half with a sharp knife.  This process is called butterflying the gizzard, because when you open it in half it vaguely looks like a butterfly

Rinse the exterior and interior of the gizzards. Remember, this organ works with gravel and dirt to grind food, so there is going to be a lot of unpleasantness in there. 

Once the gizzard is completely clean, peel away the whitish-yellow lining. If it does not easily pull away, use scissors to trim the lining from the flesh.

Thoroughly wash again in running water, drain and refrigerate until ready to be used

Trim the fat, membrane, or any other tissue attached to the heart. 

Cut the hearts open and remove any visible coagulated blood. Wash thoroughly and drain. 

Wash the chicken livers in cold water

Clean and trim them by cutting away any veiny or sinewy parts and any discolored fat.

Cut them in half and pat dry with kitchen paper.

Mix the vinegar with the water and soak the hearts and gizzards for about 30 minutes.  This helps to tenderise them a bit, minimise the metallic taste and impart a bit of tartness to the meat.

Drain the hearts and gizzards and keep.

In a heated pot, add oil and cumin seeds. Once cumin seeds start to splutter add curry leaves, onions, garlic and ginger, and cardamom pod and sauté for few seconds until fragrant.

Add the giblet pieces, and hearts, the tomato, tomato paste and bay leaves and give it a good stir.

Add the curry powder and give it a quick stir and add water and cook on low heat for about 45 minutes, stirring occasionally.

Add livers and cook for a further 15 minutes over medium-to-low heat. Do not stir too often because the livers will breakup.

Remove form heat and top-up with coriander leaves, and let curry stand for about 5 minutes.

It can be served with plain boiled rice any chutney. In our case we served it a grated apple and carrot chutney.