This is a two-stage process and for some reason, in the UK, stage one is difficult. Raw prawns are pretty easy to get although cooked ones far outnumber them in British fridges and freezers, but trying to get them raw and whole is fairly rare.
Enter “Iberian week” in Lidl where there are large boxes of frozen whole prawns for a limited time. Buy them and do this.
Stage one is to flavour the oil before going on to use it to make the dish. Peel and de-vein the prawns and flavour the oil with the heads, shells and some garlic and chilli. Then stage two is to cook the meat in the oil with some more garlic and chilli.
If you only have peeled prawns it is still nice, but it’s much better if you can get flavour from the shells and particularly the heads before you start
Method
If you have whole prawns…
… do this, if not skip to “cooking the prawns”
Put the heads and shells in a pan with the olive oil, half the garlic and half the chilli
sprinkle with the paprika and heat to medium-ish and cook everything for 10 minutes crushing the heads and shells with a wooden spoon
let it cool a bit and strain it through a sieve
cooking the prawns
wipe out the pan you just used with kitchen roll and return the oil to the pan (if you couldn’t get whole prawns simply put clean olive oil in the pan with the paprika)
return it to a medium heat and add a little extra virgin oil for a richer flavour before adding the rest of the garlic and chilli
cook it for a few minutes taking care not to brown the garlic – you don’t want it to become bitter – and then cook the prawn tails for a few minutes until cooked through
That’s it!