Preheat the oven to 400 degrees F.
Wash and inspect all of the shellfish, reserve in the refrigerator. In a large, thick, bottom pot with shallow sides, saute the onion with 1/2 of the olive oil until tender. Add chorizo and garlic, and saute for 5 minutes. Add tomato broth, saffron, 1/2 of the basil, and 1/2 of the parsley.
Bring to a boil. Add all the shellfish, rice and season with salt and pepper. Bring to a simmer, cover and finish in the oven. Cook for 10 to 15 minutes, or until rice is tender and the clams have opened. Remove from the oven and season the top with salt, pepper, the remaining parsley, basil, and the olive oil.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.