Crush ½ garlic clove*. Finely chop the onion and tomato. Coarsely chop the coriander leaves, discarding the stems.
Step 2 — Make pico de gallo
Combine the garlic and 2 tsp white wine vinegar in a large bowl. Add the onion, tomato and coriander, season with salt and pepper and stir to combine.
Step 3 — Marinate fish
Combine 2 tsp Mexican seasoning* (see Make it milder) and 1 tbs olive oil in a bowl and season with salt and pepper. Add the fish and turn to coat.
Step 4 — Cook fish
Heat a medium frypan over medium heat. Cook the fish for 3½-4 mins each side until browned and cooked through (to test the fish, flake with a fork; if it comes apart easily, it's cooked). Remove from the pan and break into large chunks.
Step 5 — Serve up
Meanwhile, trim the lettuce, then separate the leaves. Divide the fish and pico de gallo among the lettuce cups. Drizzle with the mayonnaise and enjoy!
Step 6 — Make it milder
Our Mexican seasoning has a mild chilli kick, so reduce the amount if you want to avoid the heat.