Thinly slice the onion vertically. Rinse the aosa seaweed briefly and squeeze out excess water.

In a bowl, mix the batter ingredients (flour, potato starch, and cold water) lightly.

In another bowl, combine sakura shrimp, onion, aosa seaweed, and the flour for coating. Add the batter and mix gently.

Heat vegetable oil in a pot to 170°C (about 3cm deep). Scoop 1/6 of the mixture with a spatula and drop it into the oil. Fry for 3–4 minutes, flipping occasionally until golden brown. Repeat for 6 pieces.