Boil some water in a pot. Clean the mussels carefully with some cold water and the help of a brush if they are too dirty and hairy, and throw them into the boiling water. Then, take them out as soon as they are opened. Shell them (you can keep some of them with the shell if you like) and set them aside.
Chop the spring onion, garlic and peppers into thin pieces. Clean and cut the cuttlefish or squid into rings. Remove the heads of the prawns. Dice the meat into medium cubes.
Heat two tablespoons of olive oil in a big frying pan and add the diced meat. Add salt and fry until the meat is cooked and slightly brown on the outside. Remove them from the pan and set aside for later.
Add the peppers into the same pan. Stir-fry for two minutes and then add the spring onion and garlic and cook for 10 more minutes or until soft. Then, grate the tomato on top and add the peas. Cook for 6 or 8 minutes over low heat, stirring occasionally so that it doesn’t get burnt.
Add the squid or cuttlefish. Mix everything together well and cook for another two minutes.
Add the meat you fried earlier. Add the rice, a teaspoon of sweet paprika and some strands of saffron, mixing everything together well. Pour the water on top and add some salt.
Cook over high heat for 6 minutes. Then lower your heat to the lowest setting for another 12 minutes. Keep in mind that around the 12 minute mark (4 minutes after you turned your heat down), you should add the beheaded prawns, as they will need around 8 minutes to cook. Add the mussels as well. Turn your heat back on high for the last 2 minutes. Try some of the rice, adding some salt if necessary. Turn your heat off and let rest for 2 minutes before serving.