Prawns take so well to south-east Asian flavours such as chillies, coriander and fish sauce, and never more so than in a neat little fish cake. Sometimes I sandwich the crisply fried prawn cakes in a soft, flour-dusted bun; other times I eat them between a couple of slices of hot toast. Either way, they need a spoonful of herb-flecked mayonnaise.

Makes 4
red onions 2
olive oil 3 tbsp
golden caster sugar 1 tbsp
balsamic vinegar 1 tbsp

For the prawn cakes
prawns 200g, shelled weight
coriander 20g
spring onions 3
fish sauce 3 tsp
chilli 1 small, hot
groundnut oil 2 tbsp

To finish
bread 8 thin slices
chopped coriander 2 tbsp
mayonnaise 3 tbsp

Peel the onions, halve them, then cut each half into thin segments. Warm the oil in a saucepan, add the onions then let them cook over a low heat until soft and translucent. They shouldn’t brown. Stir in the sugar and continue cooking until it starts to darken and caramelise. Add the balsamic vinegar and set aside.

Tip the prawns into the bowl of a food processor, add the coriander, spring onions, fish sauce and chilli and process briefly to combine. The texture should be soft enough to hold together when lightly pressed, but not so well mixed as to be paste-like. Remove the mixture from the bowl and shape into four small patties.

Warm the groundnut oil in a shallow pan then add the patties and let them cook for three or four minutes till lightly browned. Turn them carefully and cook the other side. Toast the bread. Chop the coriander and stir into the mayonnaise and check the seasoning. Place a spoonful of the onions and another of the coriander mayonnaise on top of each patty, then sandwich between the hot toasts.