Preparation Method
- Make the pickled radishes and carrots: Place the radishes, onion, and carrot in a large bowl, toss with the salt, and set aside for 30 minutes, stirring occasionally. Drain the vegetables in a fine-mesh sieve, then pack into a quart-sized Mason jar or airtight container. Sprinkle with the cumin seeds. Whisk together the vinegar, water, and sugar in a small bowl until the sugar dissolves, then pour over the vegetables, pressing down to submerge them. Refrigerate for at least 1 hour (and up to 1 month).
- Make the tacos: Line a plate with paper towels. Pour enough oil to fill a heavy-bottomed skillet or saute pan to a ½-inch depth. Heat the oil over medium-high heat until it reads 325F to 350F on an instant-read thermometer.
- Meanwhile, preheat the oven to 250F. Wrap the tortillas in foil and place in the oven to warm. (Alternatively, wrap the tortillas in a damp paper towel and microwave for 30 seconds just before assembling the tacos.)
- Pour the buttermilk into a shallow dish. Combine the flour and panko in another shallow dish. Season the fish with the salt. Dip the fish in the buttermilk, then dredge it in the flour-panko mixture until it's coated on all sides. Carefully place 4 or 5 pieces of fish in the hot oil and fry until golden brown on all sides, about 4 minutes. Use a slotted spoon to transfer the fish to the prepared plate and repeat with the remaining fish.
- Divide the fish evenly among the tortillas. Top each taco with sour cream, lettuce, cilantro, and a generous portion of the pickled radishes and carrots (either in the taco or on the side). Squeeze the lime wedges over the top and serve.
