Pour the prawns into a bowl and add ½ teaspoon harissa paste. Toss and keep aside.
Chop the peppers and keep aside.
Cook the pasta with salt according to pack instructions. Drain and rinse under the tap to prevent sticking. Reserve some of the liquid.
Peel and chop the onion and garlic.
Heat the oil in a saucepan under medium heat. Add the onions and allow to cook until translucent.
Add the garlic into the pan and stir for 30 secs before combining it with the two tablespoons of harissa paste. Next, add the coconut milk, chopped tomatoes and some salt to taste.
Bring the liquid to a boil, then reduce the heat. Leave for around 10 mins to allow the liquid to reduce and flavours to develop.
Add the prawns, peppers and green peas and leave to cook for 5 mins. Mix in the pasta.
If you prefer the pasta more loose, then add some of the reserved cooking water and allow it to warm through.
Remove from heat and serve.