Add the olive oil to a large pan with high sides and a heavy bottom on medium heat. Add the onions and cook until soft and semi-translucent, around 3-5 minutes.

Add the minced garlic to the pan and cook until fragrant, approximately 1 minute. Add the fresh tomatoes, tomato paste and salt to the pan and stir until mixed thoroughly.  Cook until the tomatoes soften and start to break down, around 4-5 minutes.

Add the smoked paprika, turmeric, and saffron threads, cook for 2 minutes (until spices are fragrant) and add the rice.  Cook until the rice is lightly toasted, about 2-3 minutes. Add 4 cups of stock to the pan and turn down to a low heat.

Cover and let simmer for 5 minutes; do not stir the paella as it cooks (the rice will end up golden and a bit crisp on the bottom - which is what you are after!).

Add the sliced chorizo sausage to the rice, stir lightly and cover for another 5-10 minutes or until rice has softened. Add seafood and more stock if needed and cook covered until seafood is cooked thoroughly (prawns are opaque, mussels and clams have opened), approximately 4-5 minutes.

Season with salt and pepper taste, top with fresh parsley and serve immediately.