Before you start, make sure the batter ingredients are thoroughly chilled. Mix 150 g cake flour and 30 g cornstarch in a bowl and place in the freezer for 30 minutes. You can use this time to cut the vegetables.
Dry the cut ½ yellow onions, ½ carrot, 6 boiled shrimp and 5 green beans with kitchen paper and place them in a bowl. Sprinkle with 1 tbsp cake flour and mix until evenly coated.
Preheat a small pan of cooking oil to 180 °C (356 °F). Use a small pan and fry one at a time to improve the shape. While you wait for the oil to heat up, crack 1 egg into a bowl and add 150 ml water and 100 ml carbonated water. Whisk gently until combined.
If the egg mixture becomes foamy, scoop the bubbles out with a spoon.
Pour the chilled dry ingredients into a sieve. Sift into the egg mixture one-third at a time and draw crosses using chopsticks to help prevent over mixing. It's okay if the final result has a few lumps.
Add 3 ice cubes to the batter.
Pour the batter into the bowl with the vegetables and shrimp and mix until evenly coated.
Once the oil is hot, scoop up a ladleful of mixture and carefully slide it into the hot oil. Be careful not to scoop up too much batter, focus on lifting up the ingredients.
Fry for 1 minute and 30 seconds on each side.
Transfer to a wire rack to drain any excess oil. Continue to fry one kakiage at a time.
Serve with sea salt or diluted tsuyu sauce (noodle soup base) for dipping and enjoy!