If the prawns are shell-on, you'll need to peel them. This can be done before or after cooking, but peeling them after cooking makes for a juicier, more flavourful prawn.

Grip the body of the prawn in one hand and twist the head off with the other (this can be used to make stock). Turn the prawn over and pull the shell open along the length of the belly, working from the head end downwards, prising it open so that you can pull the prawn free (you can leave the very end of the shell on or off, depending on what you prefer).

Once the shell is off, check to see if there is a black line running down the back of the prawn. This is the intestinal tract - if it's black, it's full. It's not harmful to eat, but the prawn looks better without it, and it can be a bit gritty. Removing it is called 'deveining'. Using a small, sharp knife, make a shallow cut along the length of the black line, then lift it out using the tip of the knife.

To butterfly a prawn, peel and devein as above, leaving the tail on. Then make a deep cut along the belly of the prawn, open it out and press it down so that it's flat. If you want the prawns to be straight, peel (leaving the very end of the tail on) and devein, then insert a wooden skewer along its length.

Store it

Like all shellfish, prawns go off quickly, so keep in the fridge wrapped in their original packaging or in a sealed container. Eat within 24 hours of purchase.