Heat oil over medium, then sauté chopped ginger, garlic, and shallots until pale golden and fragrant.
Added into it and mix in well-chopped tomatoes and chilies until tomatoes begin to release and spill out their juice.
Add tomato sardine and 1 cup of water. Add tamarind paste, ketchup and sweet dark soy sauce or oyster sauce. Simmer sauce for 3-4 minutes so that the flavors can infuse.
Spoon some sauce over the fish and allow everything to simmer for the remaining 2-3 minutes.
Season with salt and sugar and stir in gently. Garnish and serve – Garnish with thinly sliced scallions and serve hot immediately over steamed rice.