First, make the pickled red onions - put the finely sliced onions into a small bowl and add the white wine vinegar and pinch of salt.  Stir to combine and set aside to marinate for 30 minutes.   Stir every now and again.

While the onions are pickling, make the blackening seasoning (see Notes) - mix all of the ingredients together in an airtight container until they are well combined.

Next, season the fish on both sides with 4 tsp of the blackening seasoning and set aside on a plate (for at least 10 minutes).

Make the sriracha sour cream – mix all of the ingredients together in a small bowl until they are well combined. Set aside (refrigerate) until you're ready to assemble the tacos.

Then, heat the tortillas over a gas flame for 10 seconds on each side or on a plate in the microwave for 20 to 30 seconds.

When you’re ready to cook the fish, heat 1 tbsp of olive oil in a large non-stick frying pan over a medium to high heat.  Add the seasoned fish and cook for 2 to 3 minutes on each side.   Remove to a plate with kitchen roll and when cool enough to touch, flake into large chunks.

Assemble the tacos - put some shredded lettuce or salad leaves on the bottom of each tortilla, then add a couple of slices of avocado, some pickled onions, some chunks of fish, a drizzle of sriracha sour cream, some chopped coriander and a squeeze of fresh lime juice. Serve immediately, with some extra sour cream (optional) for anyone who needs to cool it down a bit!