Peel and remove the seeds from the apples.

Cut the apples into slices.

Prepare the batter: In a bowl, mix together flour, egg, cornflour, custard powder, and water to create a thick batter.

Heat oil in a wok or deep fryer to approximately 350°F (175°C).

Dip each apple slice into the batter, ensuring it is fully coated.

Carefully place the battered apple slices into the hot oil.

Deep fry the apple slices until golden brown and crispy. This should take a few minutes per side.

Remove the fried apple slices from the oil and place them on a wire rack or paper towels to drain excess oil.

In a separate clean wok, heat caster sugar along with water and a little oil over medium heat.

Stir constantly until the sugar melts and reaches a thread-like consistency (around 230°F or 110°C).

Carefully dip each fried apple slice into the hot sugar syrup, ensuring it is evenly coated.

Remove the candied apple slice from the sugar syrup.

Immediately dip the sugar-coated apple slice into ice water for about a minute. This will harden the sugar coating and create a crispy shell.

Remove the apple slice from the ice water and place it on a serving plate.

Serve the candied apple slices immediately while they are still warm and crispy.