Prepare the prawn and vegetables and set aside. *2
Place the flour and add icey cold water and mayonnaise. Combine them together briefly (don't over-mix or it will be too gooey).
Set aside in fridge until all ingredients and oil is ready.
Fill a deep pan or deep-fryer with vegetable oil and heat until 180c.
Add each ingredient (prawn & vegetable) to the batter individually to coat them and put them into the oil.
When the prawn and vegetable is cooked, if you lift them up out of cooking oil with a pair of chopsticks you can feel tiny vibration.
When the ingredients are cooked, place them onto a plate lined with a paper towel to absorb the excess oil.
Continue to coat and fry each ingredient until all done.
Add the mirin to a small sauce pan and boil on high heat for about 1 minute (this will allow all the alcohol to evaporate).
Add the water, soy sauce, and dashi powder and bring to a boil.
Place the sauce in a bowl and allow it to cool down then serve with the Tempura.
Pour about 1/4 cup of Tentsuyu in a small bowl with about 1 tbsp of grated daikon to serve with Tempura. *3
Tempura is quite difficult to make at home. To achieve crispy and crunchy tempura batter is to use Japanese mayonnaise. If you can not get Japanese mayonnaise, it can be omit. Instead of using Japanese mayonnaise, make all other batter ingredients really cold. Use icy cold water and keep the bowl of batter in fridge until just before it is used. *1 you can replace chikuwa with any vegetables such as green beans and shishito peppers*2 follow the tips in the post.*3 you could sprinkle shichimi togarashi (7 spice chilli) too if you like a little kick of spiciness.