Prepare the Homemade Corn Tortilla dough according to its separate recipe. Divide the rested dough into 24 equal balls of about 22g each. Keep the dough balls covered at all times so the masa does not dry out. Press each tortilla to about 11.4cm / 4.5 inches diameter and cook on a dry hot skillet or comal until lightly charred, flexible, and cooked through. Stack immediately under a towel so the tortillas steam and stay soft. Do not overcook them; they need to stay pliable for open tacos. The smaller diameter keeps the open-faced taco in proportion — a full-size tortilla would leave a single piece of fish looking sparse and make the taco awkward to eat by hand.

Combine the diced mango, red bell pepper, red onion, cilantro, lime juice, salt, and jalapeño if using. Fold gently so the mango stays in visible pieces. Taste and adjust with more lime or salt if needed. The salsa should be bright, juicy, and spoonable, not crushed into a mash. Gentle folding rather than stirring or mashing is the deciding factor between a salsa with genuine mango texture and one that turns into a wet purée — ripe mango is soft enough that vigorous mixing breaks it down almost immediately.

Blend the sour cream, chipotle peppers, adobo sauce, lime juice, salt, smoked paprika, and cumin until smooth. Add water 15ml at a time only if the crema is too thick to drizzle. The final texture should fall from a spoon in thick ribbons, not run like liquid. Blending the chipotle peppers directly into the sour cream, rather than mincing them by hand, distributes their smoky heat and colour evenly throughout the crema instead of leaving pockets of concentrated spice — the pale orange threads this produces when drizzled are as much a visual signature of the dish as a flavour one.

Toss the thinly sliced red cabbage with lime juice and salt. Let it sit for 10–15 minutes while preparing the fish. The cabbage should soften slightly but stay crisp and vivid purple. The brief lime-and-salt sit is a light quick-pickle rather than a full ferment — just enough acid and time to soften the cabbage's raw edge and draw out a little moisture, while the short window keeps it well short of losing its crunch or vivid colour.

Pat the cod pieces dry with paper towels. Season with salt, black pepper, and lime juice. Let sit for 10 minutes, then pat lightly dry again before dredging. Wet fish will make the batter slide off and fry unevenly. The second pat-dry after the 10-minute rest matters because the salt and lime juice draw moisture to the fish's surface during that time — skipping this second drying step undoes the benefit of the first one, leaving a wet surface right before the coating stage that matters most.

In one bowl, mix the dry dredge ingredients. In a second bowl, whisk the flour, cornstarch, baking powder, salt, smoked paprika, cumin, garlic powder, and cayenne. Add 330ml very cold sparkling water or lager and whisk just until combined. Add more liquid only if needed. The batter should be thick enough to coat the fish but loose enough to drip slowly. Do not overmix it. A slightly lumpy cold batter fries lighter than a perfectly smooth overworked one. Overmixing develops gluten in the flour, producing a denser, chewier crust rather than the light, shattering one this recipe is built around — a few lumps left in the batter is a sign it's been handled correctly, not a mistake to fix.

Heat neutral oil in a heavy pot to 175–180°C for deep frying. For shallow frying, use enough oil to come 1–1.5cm up the side of the skillet and heat over medium-high until shimmering. The oil temperature matters. Too cool and the batter turns greasy; too hot and the outside burns before the cod flakes. This temperature window is a genuine balance point specific to fish, which cooks through quickly — the batter needs to crisp and set at roughly the same rate the thin cod pieces cook, and oil outside this range throws that timing off in one direction or the other.

Working in batches, coat each cod piece in the dry dredge, shake off the excess, then dip into the spiced batter. Let excess batter drip off for a second, then carefully lower into the hot oil. Fry for 3–4 minutes, turning as needed, until deeply golden, crisp, and cooked through. The fish should flake easily inside and register about 60–63°C in the thickest part. Transfer to a rack, not paper towels, so the bottom stays crisp. Season lightly with salt while hot. Do not crowd the pan. Crowding drops the oil temperature and gives you pale, greasy fish instead of crisp golden fish. Salting immediately after frying, while the surface is still hot and slightly oily, is what allows the salt to actually adhere — salted fish left to cool first won't hold the seasoning nearly as well.

Just before assembly, rewarm the tortillas on a dry skillet for 10–15 seconds per side until soft and flexible. Keep them covered in a towel. This is a brief warm-through rather than a second cook, purely restoring pliability and heat right before the tacos are built.

Place 3 warm corn tortillas per serving on plates or a wooden board. Add a small handful of purple cabbage to one side of each tortilla. Place one crispy battered cod piece on each taco, keeping some of the broken white fish interior visible. Spoon mango salsa over the fish. Drizzle chipotle crema in thick pale orange threads across each taco. Finish with fresh cilantro leaves. Leaving part of the fish's flaky white interior visible, rather than covering the cod completely with toppings, is a deliberate plating choice — it signals the fish's freshness and doneness at a glance and keeps the crust's texture visible against the surrounding colour.

Serve immediately with lime wedges between the tacos. Squeeze fresh lime over the tacos just before eating. The fish should still be crisp, the cabbage fresh, the mango bright, and the crema thick enough to cling to the filling. The crisp batter is the most time-sensitive element on the plate — it begins softening the moment it sits under the moisture of the salsa and crema, so serving without delay is what preserves the contrast between crunchy fish and everything else.