Method
Place your pan over a medium heat (the pan needs to be at least 38cm wide – see note above), add the olive oil and heat for a few moments. Place the pieces of hake loin in the pan and fry them for about 3-4 minutes per side, until they have gained a bit of colour. Add the chorizo slices and cook for another 30 seconds or so, flipping them over to prevent them burning, then use a slotted spoon to lift the fish and chorizo out of the pan and into a dish, setting it aside to keep warm.
Using the oil in the same pan, cook the onions gently for 5-10 minutes until softened and translucent, with a little colour. Add the sliced peppers and green beans to the pan and cook for four minutes, or until they are beginning to soften, then stir in the garlic, smoked paprika, saffron, bay leaves and rice. Mix well and and cook for two minutes, until the rice is glistening all over. Return the hake and chorizo to the rice pan, along with any juices. Stir gently to combine, then pour in the hot stock and add a good grinding of black pepper. Stir again briefly, then bring the pan up to a simmer over a medium heat and cook for about 10 minutes, stirring from time to time. Next, add the mussels to the rice mixture, folding everything together carefully so that the mussels are nestled into the hot rice and liquid. Bring the pan back up to a simmer and cook for about three minutes, stirring occasionally, until most of the mussels have opened (discard any that are still closed at the end of the cooking time). Add the squid, prawns and parsley to the pan and stir them in (this will be the last time during cooking that you will need to stir; leaving the rice to cook allows it to become lightly browned and a little bit sticky around the edges of the pan, which all adds to the flavour of the finished dish). Continue cooking for about five minutes, until the squid and prawns are cooked, the rice is tender and almost all of the liquid has been absorbed. As you are not stirring, keep the heat fairly gentle during this time to avoid burning the rice – you can always add a bit more water if the paella begins to look dry before the rice is ready. Serve hot, with plenty of lemon wedges.