Lightly season fish head with salt and pepper. Steam for 10 minutes. Remove and discard any excess water from the plate.
Mix the water and asam jawa paste and strain the juice. Set aside. Heat oil in a saucepan. Fry blended spices and polygonum stalks until fragrant. Thin down with 2-3 tablespoons of the strained tamarind juice.
Add the rest of the tamarind juice and ladys fingers. Bring to a boil. Allow to simmer for 5-6 minutes. Add cherry tomatoes and adjust with seasoning to taste.
Dish out gravy and pour over the fish. Continue steaming for a further 3-4 minutes or until the eyes of the fish pop out.
Serve the dish with a sprinkling of sliced wild ginger bud.