Wash zucchini and trim the ends. Cut each zucchini into 1/4-inch thick rounds (about 30–36 slices total depending on size). Pat slices dry with paper towels to remove excess moisture.

Make batter

In a medium bowl whisk together 1 cup all-purpose flour, 1 tsp kosher salt, 1 tsp black pepper. In a separate bowl whisk the egg with 1 cup cold water until blended. Add the wet mixture to the flour and stir gently until just combined — you want a slightly thin, lumpy batter (similar to tempura). If too thick, add 1–2 tbsp cold water.

Set up dredging station

Place panko breadcrumbs in a shallow wide dish. Put the batter bowl next to the panko and arrange a tray lined with paper towels for draining fried zucchini. Have scallions ready for garnish.

Heat oil

In a medium heavy skillet or shallow frying pan (or a small pot) add about 1/2-inch to 1-inch of neutral oil — approximately 1.5 to 2 cups depending on pan size. Heat over medium-high until temperature reaches 350°F (175°C) or a piece of batter sizzles and browns in about 30–45 seconds.

Batter and panko coat

Working in batches to avoid crowding, dip each zucchini slice into the batter, letting excess drip off, then press both sides into the panko to coat completely. Place coated slices on a plate and repeat until the first batch is ready to fry.

Fry zucchini

Carefully slide coated slices into the hot oil in a single layer (do not overcrowd). Fry 2–3 minutes per side until golden brown and crisp. Turn once with tongs or a slotted spoon. Remove to the paper towel-lined tray and immediately season lightly with a pinch of salt. Repeat with remaining batches, maintaining oil temperature around 320–350°F (160–175°C).

Keep warm (optional)

If making ahead, keep finished zucchini on a wire rack set over a baking sheet in a 200°F (95°C) oven to keep crisp while finishing sauces and other components.

Gochujang Aioli

In a small bowl whisk together 1 cup mayonnaise, 2 tbs gochujang, 1 tsp rice vinegar, 1 tsp sesame oil, 1 tsp honey, 1/2 tsp grated garlic and 1/4 tsp salt until smooth and homogenous. Taste and adjust heat or sweetness — add up to 1 tsp more honey if too spicy, or 1/2 tsp more gochujang for more heat. Refrigerate until ready to serve.

Eel Sauce (Unagi-style)

Combine 1/2 cup soy sauce, 1/4 cup mirin, 1/4 cup sake and 3 tbs granulated sugar in a small saucepan. Bring to a gentle simmer over medium heat, stirring to dissolve the sugar. Reduce heat to low and simmer 6–8 minutes until slightly thickened and glossy.

If you prefer a slightly thicker glaze, mix 1 tsp cornstarch with 1 tsp water to make a slurry. Whisk slurry into the simmering sauce and cook 30–60 seconds until it thickens to a syrupy consistency. Remove from heat and let cool slightly; sauce will thicken more as it cools.

Finish & Assembly

Arrange fried zucchini slices on a serving platter in a single layer or slightly overlapping.

Drizzle eel sauce lightly over the zucchini, using about 2–3 tbs total (or serve extra on the side for dipping).

Dot or pipe gochujang aioli over the zucchini in thin lines or small dollops — about 1–2 tbs per 6–8 slices, adjusting to taste.

Sprinkle 2 tsp furikake evenly across the plated zucchini, then scatter about 1/2 cup bonito flakes on top so they flutter from residual heat.

Finish with the thinly sliced scallion greens and serve immediately with lemon wedges on the side if desired.