I am a broad church: when I'm not craving a bowl of food that delivers the same soothing taste from mouthful to mouthful, I like the sort of meal that involves a table full of bits and pieces, much DIY assembly and a lot of condiments. I certainly think this latter way of eating is one of the most relaxing ways of sitting around a table with friends.
These fish tacos are a case in point, and rest assured that the actual preparation is much more low-effort than you might think. For one, I roast the fish that goes in the tacos rather than, as is more traditional, fry it; the quick-pickled onions involve no more than cutting a small red onion into half-moons and steeping them in lime juice; the sweetcorn relish is mainly made out of a can (for which, no apologies) and the spicy sauce comes simply by adding some Korean gochujang into some shop-bought mayo. Yes, I know there is a little cultural melding going on here, but if you already have gochujang you will long to find uses for it. Otherwise, any shop-bought hot sauce of your choice will do.
Preheat the oven to 220 degrees C (425 degrees F)/gas mark 7 for the fish, and begin by preparing the sides for your tacos. Peel and halve the red onion, then thinly slice into half-moons. Put the red onion slices into a bowl and cover with the lime juice. Stir with a fork to mix the onion well in the juice. Actually, if you can get this done ahead of time (up to 1 day), so much the better, but even 20 minutes is fine.
Make the hot sauce by mixing together the mayonnaise and the gochujang paste (or other hot sauce) in a small bowl. Set aside.
For the corn relish, put the canned sweetcorn into a bowl. Finely dice the chile (de-seed if you don’t like too much heat) and add to the sweetcorn, along with the chopped coriander and some salt to taste. Give it all a good stir, and set aside.
Cut the fish fillets in half lengthways, so you have long fingers, and arrange in a shallow roasting dish. Mix together the cumin, paprika and salt, and sprinkle it over the fish fillets.
Mix the garlic and the oil in a small bowl. Drizzle the fish with the garlicky oil, and roast in the oven for 8 to 10 minutes, depending on the thickness of your fillets. Check to see if the fish is cooked through (though only just) before taking out of the oven.
Once you've taken the fish out (though don't let it get cold) turn off the oven and warm the tortillas in the fading heat. Meanwhile, peel, stone and slice the avocados, then spritz with the juice of the lime, ready to serve with the other accompaniments.
Arrange the fish on a plate (lined with salad leaves, if so desired), sprinkle with some chopped fresh cilantro and take it to the table along with the warmed tortillas. If you don't want to add any salad to the fish directly, you may want to put a bowl of shredded iceberg or some other crisp leaves nearby.
Put the bowls of soused, but drained, red onions, the corn relish, hot sauce and a plate of sliced avocados on the table so that everyone can load their tortillas. A plate of lime wedges and a pile of napkins are both good ideas, too.
The pickled onions, hot sauce and relish (minus the cilantro) can be made 1 day ahead. Cover and refrigerate until needed. Stir the chopped coriander into the corn relish just before serving.