Step 1

To make the chermoula butter, whiz the butter, chilli, garlic and half each of the lemon zest, cumin, paprika and coriander in a small food processor until combined. Place a 30cm long sheet of baking paper on a work surface and top with butter mixture. Form into a 12cm log, then roll up baking paper and twist ends to secure. Chill for 1 hour or until firm.

Step 2

Place the couscous, remaining lemon zest, cumin and paprika, and 1 tsp sea salt in a bowl and stir to combine. Cover with 1 cup (250ml) boiling water, then cover with a tea towel and set aside for 15 minutes or until liquid is absorbed.

Step 3

Meanwhile, heat oil in a frypan or wok over high heat. Season prawns, then cook, turning once, for 3-4 minutes until prawns turn pink. Slice chermoula butter into four 3cm-thick slices and add to the pan, tossing the prawns to coat.

Step 4

Fluff the couscous with a fork, then add onion and remaining coriander, and stir to combine. Divide couscous among plates, and top with prawns, extra chilli and whole coriander leaves to serve.