「PREP」Make tempura batter. Peel the carrot and onion, and cut the tops off the green beans. Cut carrot and onion into thin slices. Cut the green beans into 1-2cm long pieces.
Put the cut veggies in a bowl, add the flour and lightly mix.
Heat the oil to 175ºC. Add the flour-coated veggies to the tempura batter and gently mix until just coated.
Use a ladle and cooking chopsticks to scoop a clump of batter-coated veggies and lower it into the deep-frying pot*. Use the chopsticks to scatter and mix the veggies, then gather them together again. A mesh skimmer comes in handy here.
Fry for 1-1.5 minutes per side, then remove from oil and drain on a paper towel-lined rack. Serve hot, with tentsuyu for dipping.
Notes
* The oil temperature will decrease slightly as you add the cold batter and veggies to it. Try to maintain the temperature at a consistent 175ºC to ensure the batter doesn't get soggy (not hot enough) or burn (too hot).