Prepare the ingredients by cutting and slicing to bite size.
Spear the prepared ingredients with skewers and set aside.
Mix the egg, flour, water and mayonnaise in a small bowl to make a batter.
Coat all skewered ingredients with batter, then coat with the panko crumbs.
Heat frying oil in a deep pan that is a deep enough so the skewers can be dipped in, until it reaches around 180 degrees Celsius.
Deep fry each skewer until it’s crispy and golden brown.
Place all sauce ingredients in a small saucepan over medium heat.
Combine and stir until all ingredients dissolve. Turn the heat off just before it boils.
Serve Kushikatsu with the dipping sauce.
This is what I have learnt from a Japanese chef. Chop off prawns' tails so that when it is deep-fried, the air escapes from the cut to prevents oil from spattering. Calories are estimate only as it is hard to accurately calculate the amount of oil used for deep fry.