Chop the scallions into 3-inch pieces and slice the onion julienne. Set aside.
Pat dry the shrimp and scallops and chop them up in big chunks.
Make the batter by combining all-purpose flour, potato starch, egg, water, salt, pepper, hondashi, and minced garlic. Mix well then taste and adjust accordingly. Add salt, pepper, and hondashi as needed.
Add the scallions and onion into the batter and mix well until everything is coated. Check the consistency of the batter, it should be a little thick. Adjust the batter as needed, add water if it’s too thick, and add flour and potato starch if it’s too loose.
In a nonstick pan, on high heat, heat up a generous amount of oil until there is a bit of white smoke coming out.
Once the oil is heated, add a handful of batter and shape it into a thin wide circle as quickly as you can. Top the pancake with seafood.
Cook the pancake for 2 minutes on high heat on each side, then 2 minutes on medium heat on each side. Add a round of oil as needed every flip to crisp up the pancake.
Watch out for white smoke, and flip as needed. Flatten to crisp it up and do taps to check if the inside is cooked through.
Cook until the pancake is golden brown.
Serve hot with a dipping sauce and enjoy!