Pangat is poached fish that is cooked with the use of a souring agent. The most commonly used are Calamansi (Philippine lime), tamarind and kamias (Bilimbi). These fruits are indigenous to the Philippines and Southeast Asia. Calamansi juice or extract are now sold frozen in sachets here in the Northeast. (see photo below).
This is a simple dish that is fairly easy to make. You just need the following ingredients: tilapia, onions, tomatoes, juice of calamansi, lemon, salt and water. Slice your onions, tomatoes and lemon and layer it into a pan. Place your Tilapia on top of the vegetables. I prefer to use fresh whole tilapia from the Asian store where they can gut, clean and cut it for you. You can add more slices of tomatoes, onions and lemons on top of the fish for added flavor. Sprinkle kosher salt and pour in your calamansi extract and 1/2 cup of water. Simmer until fish is done and can easily be flaked with a fork. Do not overcook.