Combine the pork with the grated onion, garlic, ginger, baking soda, 2 tsp cornflour/cornstarch, and soy sauce, then refrigerate for 18 to 24 hours. The pork should look evenly coated with the aromatic marinade before chilling.

Heat the oven to 80°C/175°F and place a wire rack over a baking tray. This warm resting spot keeps fried batches elevated so their coating stays drier.

Whisk all sauce ingredients except the water in a large jug or small bowl, then stir in the water. The mixture should look smooth, with no dry cornstarch sitting at the bottom.

Arrange the sauce mixture, pineapple, aromatics, onion, and bell peppers beside the stove before frying. Everything should be within reach because the pork needs to be sauced immediately after its second fry.

Work 5 tbsp cornflour/cornstarch into the marinated pork and leave it for 5 minutes. The initially white coating will turn damp, tacky, and slightly glossy as it absorbs moisture.

Spread the 1/2 cup cornflour/cornstarch in a shallow bowl, then coat each piece and shake away loose excess. The pork should still look at least half white with dry starch when it goes into the oil, so dust again if needed.

Pour vegetable or canola oil into a large saucepan or small pot to a depth of 2.5cm / 1', then heat it to 180°C/350°F. A test piece should begin sizzling immediately without the oil smoking.

Fry the pork in uncrowded batches for 3 minutes, then transfer each batch to the rack. This first fry cooks the pork and gives the coating a pale golden finish rather than deep browning.

Raise the oil to 200°C/390°F and fry the coolest pork first, working in two batches for 1 1/2 minutes each. The sizzle becomes sharper and the pieces turn deep golden brown with a firm, blistered crust.

Return the twice-fried pork to the rack and keep it warm in the oven while finishing the stir-fry. Keeping the pieces in a single layer helps steam escape instead of softening the crust.

Heat 1 tbsp oil in a very large skillet over high heat, then stir-fry the garlic, ginger, and onion for 1 1/2 minutes before adding the bell peppers for 2 minutes. The aromatics should smell fragrant and the vegetables should stay bright with crisp edges.

Pour in the prepared sauce and pineapple, then bring the mixture to a rapid simmer for 2 minutes. The sauce is ready when it turns glossy and a dragged spoon leaves a brief path across the skillet.

Add the hot fried pork and toss it through the sauce for no more than 10 seconds. Every piece should pick up a thin shiny coating while the crust still sounds crisp against the skillet.

Transfer the pork and vegetables to a serving platter immediately. The coating is at its crunchiest straight away and gradually softens once it meets the sauce.