Directions

1. 1

   In a large bowl, combine 1 1/2 cups water, lime juice, sliced garlic cloves, serrano chiles, oregano, and sea salt. Stir well to blend. Add the shark fillet strips and gently mix to coat evenly. Cover and refrigerate for at least 20 minutes to allow the fish to absorb the citrus and spice flavors.

2. 2

   While the fish marinates, prepare the tempura batter. In a separate bowl, whisk together the ice water and yellow mustard until combined. Add the flour and gently stir with a fork or whisk just until incorporated; the batter should be lumpy, not smooth. Cover the bowl with plastic wrap and refrigerate for 30 minutes.

3. 3

   Remove the marinated shark strips from the bowl and lay them on paper towels. Pat them thoroughly dry with additional paper towels to remove excess marinade. Have a clean plate lined with fresh paper towels ready for draining the fried fish.

4. 4

   In a large, heavy-bottomed pot or deep fryer, pour vegetable oil to a depth of at least 2-3 inches. Heat the oil over medium heat to exactly 360°F, as measured by a deep-fat thermometer. This is critical for achieving crispy, golden fish without greasiness or burning.

5. 5

   Remove the tempura batter from the refrigerator and stir once gently. Working with 2-4 pieces at a time, dredge the dried shark strips in the batter, shaking off excess, and carefully place them into the hot oil. Add 2 more pieces every 30 seconds, maintaining no more than 4 pieces in the oil at once.

6. 6

   Monitor the oil temperature continuously throughout frying, keeping it between 360°F and 380°F. If the temperature drops, wait for it to return to 360°F before adding more pieces. If it rises above 380°F, reduce heat slightly. Fry each batch for approximately 2 1/2 minutes until the pieces are crisp, light golden brown, and floating in the oil.

7. 7

   Using a fine-mesh skimmer, carefully remove each batch of fried fish and transfer to the paper-towel-lined plate. This absorbs excess oil. Skim any loose batter pieces from the oil surface between batches to prevent them from burning and tainting the flavor. Continue frying the remaining shark strips.

8. 8

   Warm the corn tortillas just before serving. To assemble the tacos, lay tortillas side by side on a serving platter. Divide the coleslaw equally among the tortillas, then top each with a piece of tempura shark. Garnish with lime wedges and sliced jalapeños.

9. 9

   Serve immediately while the tempura is still warm and crispy. Each person can grab a tortilla, fold it, and eat right away. Alternatively, offer ingredients separately and allow guests to build their own tacos by layering coleslaw, tempura fish, and jalapeños on a tortilla before folding and eating.