Drain the fish roe in a fine-mesh sieve set over a bowl for 10 minutes to remove excess liquid. Pat dry gently with paper towels. Cut the white fish fillet into roughly 2–3 cm pieces and chill for 5 minutes to keep firm while processing.

Make fish paste (surimi base)

In a food processor, combine the chilled white fish pieces, cold water, and egg white. Pulse until the mixture becomes a smooth, sticky paste (about 30–45 seconds). Scrape down the bowl as needed.

Incorporate roe and seasonings

Transfer the fish paste to a mixing bowl. Gently fold in the drained fish roe, cornstarch, breadcrumbs, salt, white pepper, chopped scallion, and chopped dill (if using). Use a rubber spatula to mix, taking care not to overwork and burst too many roe eggs. The mixture should hold together when pressed; if too loose, add 1 tbs more breadcrumbs.

Form balls

Wet your hands slightly to prevent sticking. Scoop approximately 1 tablespoon (about 20–25 g) of mixture and roll gently between your palms to form compact balls about 2.5–3 cm in diameter. Place formed balls on a parchment-lined tray. Repeat until all mixture is used (yields ~16–18 balls).

Chill

Cover the tray and chill the formed balls in the refrigerator for 15–20 minutes to firm up; this helps them hold shape during frying.

Fry

Pour the neutral oil into a medium skillet or shallow frying pan to a depth of about 1–1.5 cm and heat over medium heat to 170–175°C (340–350°F) or until a small breadcrumb sizzles when dropped in. Fry balls in batches (do not overcrowd) for 2–3 minutes per side, turning gently with a slotted spoon or tongs, until golden and cooked through. Internal temperature should reach 60–65°C (140–150°F). Remove to a paper-towel-lined tray to drain excess oil.

Finish and serve

Transfer the fried roe balls to a serving plate, squeeze a little lemon over them, and garnish with extra chopped scallion or dill if desired. Serve hot with the dipping sauce.

Dipping Sauce

Combine yogurt (or crème fraîche), mayonnaise, lemon juice, chopped chives, hot sauce (if using), salt, and pepper in a small bowl. Stir until smooth and taste; adjust seasoning with more lemon or salt if needed. Chill briefly while balls rest. Serve alongside the warm roe balls.