In a small container, combine the spices and set aside. Then chop the prawns, place in a small bowl and cover in as much of the spice mix as you would like (it’s completely up to you)
Add a glug of oil and the onions to a frying pan. Cook on a medium high heat stirring occasionally until the onions start to sizzle a little. Add the tomatoes and continue cooking until onions are translucent.
Add the prawns to the pan, stirring occasionally until thooked through. Remove from the heat and serve tacos with guacamole, coriander and sour cream.
When adding the tomatoes, add some chives or spring onions to add some more flavour.
We use corn tortillas, and steam them in non-stick pan without using oil (if you want yours a little crispier, you can fry them in oil until soft)