Prepare the shrimps by removing their heads and shells, while leaving the tails on.
Pour 2 ½ cups of oil in a deep frying pan and set it on the stove on medium heat when you are almost done cleaning the shrimps. At the time of frying, the temperature of the oil should be 338 degrees Fahrenheit. You can use a thermometer or chopsticks to check the temperature of the oil. If using chopsticks, simply dip them in the hot oil and if you see small bubbles around them, this means the oil is ready for frying.
As the oil gets close to 338 degrees Fahrenheit, start preparing the batter for tempuras. Sift ¾ cup of all-purpose flour, half teaspoon of baking powder and ¼ teaspoon of salt into a bowl.
In another bowl, gently beat the egg yolk and add 200 ml of ice cold water to it. Also add two ice cubes to the bowl and pour this mixture into the bowl containing sifted dry ingredients.
Mix the batter with chopsticks, but do not make a smooth paste.
Sprinkle corn starch on the top of the shrimps, making sure they have been thoroughly covered with the starch.
Check the oil for the ideal deep frying temperature (338 degrees Fahrenheit), then dip the shrimp in the batter several times to cover it completely with the batter.
Deep fry the shrimps in the hot oil for 2 to 3 minutes or until crisp and golden brown. Set the fried tempuras on a wire rack to drain extra oil before serving.