SWEET AND SOUR FISH

Ingredients

• 1 large, well cleaned whole fish (Ask your fishmonger to clean and scale it for you. A firm-fleshed fish such as snapper, sea bass, or carp works well. Pat completely dry with paper towels before frying so the skin crisps properly.)
• 1 cup pickled onions (Use store-bought pickled onions. Slice them thin before measuring.)
• 1 cup (combined with pickled onions to total 1 cup) pickled cucumbers (Use store-bought pickled cucumbers (gherkins or cornichons). Slice thin. The pickled onions and cucumbers together make up the 1-cup total.)
• 2 whole large fresh onions (Peel and slice as fine (thin) as possible — aim for rings or half-rings about 2 mm thick.)
• 1 cup cider vinegar (This single cup of vinegar does double duty — first for soaking the vegetables, then as the base of the sauce. Do not discard it between steps.)
• 1 piece fresh ginger (One piece roughly the size of your thumb (about 5 cm / 2 inches). No need to peel for soaking, but peel it if you plan to serve it. It is used to flavour the vinegar soak.)
• 1 whole red bell pepper (Remove seeds and white pith. Slice into thin strips or rings.)
• 1 whole green bell pepper (Remove seeds and white pith. Slice into thin strips or rings.)
• 2 tablespoons sugar (Plain white granulated sugar. Used in two places — a little in the vinegar soak and the remainder in the sauce. Divide as needed between steps.)
• 1 to taste salt (Used in the vinegar soak, to rub the fish, and in the sauce. Use fine table salt or fine sea salt.)
• 1 to taste black pepper (Freshly ground is best. Used to rub the fish and season the sauce.)
• 1 to taste Chinese soy bean sauce (soy sauce) (The original recipe calls for Chinese soy bean sauce — standard Chinese soy sauce (light soy sauce) is a faithful modern equivalent. Add a little at a time and taste as you go.)
• 1 enough to deep-fry (approx. 4–6 cups) cooking oil or lard (You need enough oil to fully submerge the fish (deep-frying). A neutral oil such as vegetable or sunflower oil works well. Lard was the traditional choice and gives extra flavour. A small amount is also used to grease the pan for the sauce.)
• 1 to taste (approx. 1–2 tablespoons) cornstarch (Used to thicken the sauce into a medium-bodied gravy. Mix with a small amount of cold water before adding to the hot liquid to prevent lumps.)

Instructions

1. 1Pour the 1 cup of cider vinegar into a small saucepan. Add a pinch of salt, a little of the sugar (reserve the rest for the sauce), and the piece of fresh ginger. Bring to a boil over medium-high heat, stirring to dissolve the salt and sugar. Boil for 1–2 minutes so the ginger can infuse the vinegar. Remove from the heat and allow it to cool slightly — it should still be very hot but not aggressively bubbling before you add the vegetables.
2. 2Place the thinly sliced fresh onions and the sliced red and green bell peppers into a heatproof bowl or container. Pour the hot spiced vinegar over them — make sure all the vegetables are submerged. Cover the bowl with a lid or cling film. Leave to soak at room temperature for three full hours. This soak softens the raw sharpness of the onion and pepper and infuses them with the sweet-sour vinegar. Do NOT discard the soaking vinegar when the time is up — you will use it again in later steps.
3. 3While you are waiting for the vegetables to finish soaking, prepare your fish. Pat the cleaned whole fish completely dry on both sides and inside the cavity using paper towels — removing all moisture is the key to getting a crisp skin. Sprinkle salt and black pepper generously over the entire outside of the fish (both sides) and rub it in evenly with your hands. Set aside on a plate until you are ready to fry.
4. 4Pour enough cooking oil or lard into a large, deep, heavy-bottomed pot or wok to fully submerge the fish — typically 4 to 6 cups depending on pot size. Heat the oil over medium-high heat until it reaches approximately 180 °C (350 °F). If you do not have a thermometer, test by dipping the tip of a wooden chopstick or spoon handle into the oil — if bubbles form steadily around it, the oil is ready. Carefully lower the fish into the hot oil using tongs or a large spider strainer. Be very careful as hot oil may splatter — lower the fish away from you. Fry the fish, turning once if needed, until the skin is deeply golden-brown and crisp all over and the flesh is cooked through. This will take approximately 8 to 12 minutes depending on the size and thickness of the fish. The fish is done when a skewer inserted into the thickest part meets no resistance and the flesh is opaque and white.
5. 5Once the fish skin is crisp and golden-brown and the fish is cooked through, carefully lift it out of the hot oil using tongs or a large spider strainer. Hold it over the pot for a few seconds to allow excess oil to drip off. Place the fish on a large serving platter. Set aside while you prepare the sauce and vegetables.
6. 6After the full three-hour soak, place a colander or sieve over a bowl. Pour the soaked onions and peppers into the colander so all the soaking vinegar drains into the bowl beneath. Keep the drained onions and peppers to one side. Pour the collected vinegar back into its original container — you will use every drop of it in the sauce.
7. 7Take the drained soaked onions and peppers and scatter them evenly over the top of the fried fish on the platter. Arrange them nicely so the fish is well covered. Set the platter aside while you make the sauce.
8. 8Grease a large frying pan or wok with a small amount of the same cooking oil or lard used for frying. Heat the pan over medium heat. Pour in the reserved soaking vinegar from step 6. Bring the vinegar to a boil. Add the remaining sugar, salt, black pepper, and soy sauce to taste — start with a small splash of soy sauce and a pinch each of salt and pepper, stir, taste, and adjust. The sauce should taste distinctly sweet and sour with a savoury depth from the soy sauce. Stir well to combine.
9. 9Add the sliced pickled onions and pickled cucumbers directly into the boiling seasoned vinegar sauce in the pan. Stir gently to coat them. Bring everything back to a boil and let it bubble for 1–2 minutes so the pickled vegetables warm through and their flavour mingles with the sauce.
10. 10Using a slotted spoon or tongs, scoop the cooked pickled onions and cucumbers out of the sauce and spread them evenly on top of the fish on the platter, layering them over the soaked fresh onions and peppers already placed there. Do NOT discard the sauce remaining in the pan — you will use it immediately to make the gravy.
11. 11In a small bowl or cup, mix approximately 1 to 2 tablespoons of cornstarch with an equal amount of cold water. Stir until completely smooth with no lumps — this is called a cornstarch slurry. Keep the remaining vinegar sauce in the pan at a gentle boil over medium heat. While stirring the sauce constantly, slowly pour in the cornstarch slurry in a thin stream. Keep stirring as the sauce thickens. You are aiming for a medium-bodied gravy that coats the back of a spoon but still pours easily. If the gravy is too thin, mix a little more cornstarch with cold water and add it gradually. If it is too thick, add a splash of water and stir. Once it reaches the right consistency, taste and adjust seasoning if needed.
12. 12Carefully pour the hot cornstarch gravy evenly over the entire fish and all the vegetables on the platter. The gravy should pool around and over everything, coating the crisp fish and the layered vegetables in a glossy, tangy-sweet sauce. Serve immediately while the fish skin still has some crispness and the gravy is hot. Bring the whole platter to the table and serve directly from it.