Ready-made spring roll wrappers usually come frozen. Defrost in the fridge the night before.
Mix the filling
Put all the ingredients for the filling into a large mixing bowl (NB: leave out one egg yolk for brushing the wrappers).
Add all the seasonings. Mix until well combined (It’s best to do so with your hands. Wear kitchen gloves if available).
Assemble the rolls
Gently separate the spring roll wrappers one by one. Remember to always cover them with a clean damp cloth as they dry out easily.
Place one wrapper on a flat surface with one of the four corners facing towards you. Put about 3 tablespoon of the filling above the closest corner (Use a spoon to help shape it into a rectangle).
Lift the closest corner to wrap the filling then roll it to the half-line of the wrapper. Try to wrap it as tight as possible without leaving any air pockets inside. But be gentle during this process to avoid tearing.
Lightly press two ends of the filling then fold the left and right corners of the wrapper towards the middle.
Roll the cylinder until only a triangle is left at the top. Brush a layer of egg yolk over the triangle. Roll again to seal completely. Repeat to assemble all the rolls.
Option 1: Deep fry the rolls
Heat the oil for deep frying until it reaches 180°C/350°F. Gently slide in the rolls one by one (Do not overcrowd. Fry them in batches if necessary).
Fry over medium heat. Flip over a few times to ensure even browning. When they become golden, transfer out to a tray lined with kitchen paper to absorb excess oil.
Option 2: Air fry the rolls
Preheat the air fryer at 200°C/390°F for 3 minutes. While waiting, brush a layer of oil all around the spring rolls.
Put the rolls over the crisper tray of the air fryer in a single layer. Leave to cook for 8-10 minutes. Then flip over and cook for a further 5 minutes until they become golden.
Serve and reheat
Serve warm on their own or with the dipping sauce.
To reheat leftover spring rolls, put them in a preheated oven at 200°C/390°F for about 5 minutes, or in an air-fryer at 200°C/390°F for 3 minutes or so.
Make ahead
You may store uncooked spring rolls, right after they’re assembled, in the freezer for up to three months (Keep them in an air-tight bag/container).
Cook as usual without defrosting. If deep frying, raise the temperature to 190°C/375°F. If air-frying, prolong the cooking time by 3-5 minutes.
Video
Notes
1. If your spring roll wrappers are of a different size, please adjust the filling volume and frying time accordingly.2. Here are two vegetarian/vegan substitutes for the regular oyster sauce: vegetarian oyster flavored sauce and mushroom vegetarian stir-fry sauce. Gluten-free oyster sauce is also available.3. Use neutral cooking oil that has a high smoking point, e.g. sunflower, rapeseeds, canola, peanut, soybean, vegetable oil, etc.