Bring 1 Litre of fish stock to a simmer in a saucepan. If you can't find fish stock, then use chicken or vegetable stock.
Keep the fish stock warm until you're ready to add it later.
Combine the Paella rice, chopped artichoke hearts, freshly chopped tomatoes, Chorizo, Paella seasoning, sweet paprika, and frozen peas in a separate bowl.
Dice the chicken breast into 2cm pieces, removing any fat.
Chop the cloves of garlic and dice the spring onions making sure to discard the white part.
You will need a pan that is at least 40cm wide and about 5-7cm deep.
Add the olive oil to the paella pan and turn heat to medium-high. Once the olive oil is relatively warm, add the diced chicken and cook for about 1 minute on each side.
Add the garlic and spring onions. Cook for another minute.
Next, add the Paella rice, chopped artichoke hearts, freshly chopped tomatoes, Chorizo, Paella seasoning, sweet paprika, and frozen peas to the paella pan.
Combine ingredients gently with a spoon and then add the 500ml of the fish stock and season with salt and pepper to taste.
Bring the ingredients to a gentle boil, turn down the heat and simmer for 15 minutes, adding more fish stock as it is absorbed. Gently scrape the bottom of the pan once in awhile to prevent burning. Some people prefer to leave it, as the ingredients carmelise and add more flavour to the dish. The choice is yours!
After 12 minutes, add your fresh uncooked mussels to the paella. Try and place them hinge side down so you will be able to see when they've opened.
After 2-3 minutes, the mussels should open. Discard any that don't!!
At this point, place the cooked langostines on top of the paella for another minute or two just until they are warmed.
Serve this dish warm with crusty bread!