Preparation:

1. Combine the wine and broth in a heavy 4 quart saucepan and heat over high heat to boiling. Add the mussels, cover and steam just until opened, about 4 minutes. Remove with a slotted spoon. When cool, remove mussels from shells. 2. Add the shrimp shells to the steaming liquid, reduce heat; simmer, covered, 15 minutes. Strain cooking liquid through a sieve lined with cheesecloth. Add enough liquid to measure 4 cups. Keep this liquid just below simmering over very low heat. 3. Heat 1 tablespoon of the butter and the olive oil in a heavy 3 quart saucepan over low heat until the butter foams. Stir in the onion and cook, stirring occasionally, until the onion is tender and golden yellow, but not browned, about 15 minutes. 4. Stir in the rice and increase heat to medium. Stir until the edges of the rice are transparent, about 5 minutes. 5. Pour enough broth into the pan to cover the rice by 1/4 inch. Adjust heat to maintain a lively simmer--but not a steady boil--simmer, stirring constantly, until the liquid is absorbed and you can see the bottom of the pan when you stir the rice, about 5 minutes. Continue adding liquid, each time adding just enough liquid to cover the rice by 1/4 inch and simmering until the rice has absorbed the liquid and is tender but still firm in the center, about 20 minutes. Season to taste with salt and pepper halfway through the cooking. About 5 minutes before rice is cooked, stir in the shrimp and scallops. 6. Remove from the heat and add enough of the remaining liquid to form a creamy sauce. Stir in the mussels, remaining butter, parsley and cheese, if using. Adjust seasoning and serve immediately.
Per Serving: 332 Calories (29.4% from fat); 10g Fat (3g Sat, 5g Mono, 1g Poly); 19g Protein; 35g Carbohydrate; trace Dietary Fiber; 71mg Cholesterol; 376mg Sodium.  Food Exchanges: 2 Grain (Starch); 2 1/2 Lean Meat; 1 1/2 Fat.