Bring stock to a simmer in a saucepan; add the saffron and leave to infuse.
Heat the oil in a shallow pan on medium-high heat and fry the chorizo until it starts to brown and release its orange-colored oils. Add the onion and continue to fry until the onion has softened. Add the garlic and fry another minute.
Add the shrimp and sauté until pink (about 2-3 minutes). Remove the shrimp from the pan and set aside.
Add the white wine and allow to almost fully evaporate before adding the rice. Coat the rice with the other ingredients and then add the stock, paprika, tomatoes, and parsley. Bring to a boil before reducing the heat. Cover and leave to simmer 15-20 or until the rice is tender.
Remove from the heat, add the shrimp mix to warm with the cooked rice and serve.
* This recipe calls for parboiled or converted rice. In the US, look for Uncle Bens Converted Rice, or Golden Canilla Parboiled Rice. In the UK, buy Uncle Bens Long Grain Rice (not quick cook).
Substituting The RiceYou can use other types of long-grain rice (although I don't recommend instant, quick-cook, or brown rice). Just be sure to consult the package instructions for the rice to liquid ratios and cooking times and adjust accordingly.