Preheat the oven to 180°C.

Peel and devein the prawns but save the shells, trimming off the eyes and feelers only.

In a pan over medium heat, infuse olive oil with fresh parsley stems. Add the shells and cook until it turns orange. If you are using tomatoes, add them at this stage too. Deglaze with white wine.

Remove the parsley stems and transfer everything to a tall beaker. Add tomato paste and salt to taste. Blend until smooth.

Strain through a fine mesh sieve and transfer the bisque back to the pan. Squeeze as much liquid out as possible.

Transfer the shells to a lined baking tray and flatten. Bake for 10-15 mins, or until fully dehydrated and crisp.

Boil a pot of water and cook the spaghetti.

Heat up the bisque over low heat and cook the prawns until it just turns orange. Take them out of the pan to rest.

With a food processor, blend the baked shells into a fine bisque powder. Keep aside.

Add the spaghetti directly into the bisque and add ladles of pasta water until creamy.

Add finely chopped parsley and the prawn pieces back into the pasta and toss.