Combine cornflour with 2 tsp water in a large bowl, add prawns, soy sauce, egg yolk and sesame oil and mix to combine.
For honey and garlic sauce, combine ingredients in a bowl and set aside.
Heat vegetable oil in a wok over high heat, add half the prawns and cook for 1 minute. Using a slotted spoon, transfer prawns to an absorbent paper-lined plate and repeat with remaining prawns.
Carefully drain oil from wok and wipe clean with absorbent paper. Heat wok over medium heat, add honey and garlic sauce and simmer for 1½ minutes, then add prawns and cook for 30 seconds or until prawns are hot. Serve immediately.