Clean the mussels carefully, scraping the shells with a knife and washing them under the tap. Put in a saucepan with the wine over a medium heat with the lid on. When they have opened, turn off the heat.
Use the liquid in the saucepan to make a marinara sauce: peel and slice the garlic and then gently fry over a low heat in extra-virgin olive oil until it starts to turn golden.
Cover with the tomato puree and the liquid from the mussels and leave to simmer for a few minutes until the sauce has reduced. Add the cayenne pepper, peeled prawns and mussels (without their shells). The prawns won’t need more than 1 minute. Put by.
Boil the spaghetti following the instructions on the packet. Strain and add directly to the marinara sauce. Sprinkle some finely chopped parsley on top.