Rinse the shrimp and cuttlefish, then pat dry and cut into small cubes.
In a food processor, pulse the shrimp and cuttlefish until smooth. Transfer to a bowl.
Add 1 egg white, granulated sugar, potato starch, sea salt flakes, and freshly ground white pepper to the processed seafood; mix until well combined and season to taste.
Cut sugar cane into 10 cm (4 in) pieces and peel the outer hard shell; slice each into sticks about 1.2 cm thick (about 1/4 inch).
Oil your palms lightly. Portion about 40 g (1 1/2 oz) of the seafood mixture and shape into an oval quenelle around a sugar cane stick, smoothing the mixture so it adheres.
Place formed sugar cane shrimp on parchment and chill in the refrigerator to firm up for a few minutes.
Beat the remaining egg white in a shallow dish. Dip each chilled shrimp-on-sugar-cane into the egg white, then coat evenly with Japanese breadcrumbs.
Heat enough vegetable oil in a wok or deep pot over high heat for deep frying. Fry the coated shrimp on sugar cane in batches until golden brown and cooked through, about 2–4 minutes per batch depending on size.
Remove with tongs or a slotted spoon and drain on paper towels. Serve immediately with Nuoc Cham for dipping.
