1. Put saffron in small dish, pour a half cup chicken stock over it and set aside.
2. Heat one tablespoon oil in large skillet to very hot, add shrimp and stir. Sprinkle with paprika and stir-fry just until shrimp begin to brown but are not fully cooked, 2-4 minutes. Season with cayenne pepper and remove from heat.
3. Add butter and remaining oil and reheat. Add onion and garlic and saute until soft, working up anything stuck to the skillet, 5-6 minutes. Add the chorizo, saute a couple of minutes more, then stir in cumin and rice. Saute, stirring, until the rice turns opaque, 5-6 minutes. Stir in the saffron mixture and wine. Cook, stirring with wooden spoon over medium heat, until most of the liquid has evaporated.
4. Add about 1/2 cup of the hot broth to the rice, stirring constantly until the broth is absorbed. Continue adding the remaining broth 1/2 cup at a time, waiting until each addition is absorbed before adding more. Continue until the rice is tender, about 35 to 45 minutes. The rice should have a creamy consistency. Add the reserved shrimp, parmesan, parsley and adjust the seasoning with salt and pepper. Serve at once.