The Preparation
Prepare vegetables and seafood: peel and slice sweet potato thinly, peel and devein shrimp, cut vegetables into bite-size pieces.
Heat oil to 350-375°F in a deep pot.
In a bowl set over ice, briefly mix flour, cornstarch, baking soda, egg yolk, and ice-cold sparkling water. Do not overmix — lumps are fine. The cold temperature is key to keeping the batter light.
Dip vegetables and seafood into batter and immediately place into hot oil.
Fry in small batches to maintain oil temperature, 2-3 minutes until light golden.
Drain on a wire rack.
Season immediately with salt and serve with dashi dipping sauce.