These fried fish tacos start with juicy cod in a light, crackly beer batter, then get topped with a fresh lettuce-tomato salad, spicy sambal mayo, and pickled red onions. Crispy, fresh, spicy, and balanced.
If you're making your own pickled red onions, bring all ingredients aside from onions to a boil, pour over onions, and let cool to room temperature. Best made the day before.
Cut fish into 16–20 evenly thick planks that are approximately 1.5 ounces each, 4 inches long and 1–1½ inches wide. Season all sides lightly with salt and refrigerate uncovered.
Whisk together 75 grams all-purpose flour, 75 grams rice flour, 2 grams salt and 2 grams baking powder. Slowly whisk in most of the beer until smooth and about the consistency of thin pancake batter. Add more beer if needed, then refrigerate until ready to fry.
Cut the lettuce into short, thin strips. Small-dice the tomato, keeping its juice and seed pulp. Chop the cilantro and finely dice the jalapeño, if using. Keep everything separate for now. You'll combine later.
Stir together the mayonnaise and sambal.
To prep for frying, fill a large, heavy-bottomed pot no more than halfway with neutral oil. Set up a thermometer, a wire rack over a sheet tray, a spider and a fork next to the fry pot. Heat the oil to 375°F (190℃). Mix 25 grams all-purpose flour and 25 grams rice flour on a tray for the dredge.
Remove the fish and batter from the refrigerator. Lightly dredge all the fish, shaking off any visible excess.
Coat each piece of fish in batter, letting excess drip off. Using a fork to support the fish from below, slowly lower one end into the oil away from your body. Hold it near the surface for a second so the batter begins to set, then release into the oil.
Fry about six pieces at a time without letting them touch. Keep the oil temperature between 350℉ (176℃) and 365℉ (185℃) and fry for 3-5 minutes until deeply golden and crisp. When cooked, fish should be opaque, flake easily and reach 145℉ (63℃) in the thickest part. Carefully lift fish with spider or slotted spoon and drain on a wire rack. Allow oil to return to 375°F (190℃) before frying the next batch.
While second batch fries, make the salad slaw by combining lettuce, tomato and its juices, cilantro jalapeno, lime juice, and 2 g salt.
Warm the tortillas to heat through in a nonstick pan. Spread each with a thin layer of spicy mayo, then add the fried fish, salad, slaw, and pickled red onions. Serve immediately.
I recommend using a tortilla warmer or towel covered plate to keep tortillas warm and pliable while you're heating them.