Heat the Stock
In a heavy-bottomed soup kettle (approx. 12" diameter and 4" to 6" deep), heat 1or 2 tablespoons Olive Oil and when hot, add the onions and the rice. Toss constantly until the grains turn light gold in color.
Add the wine and the saffron. When the rice has absorbed all the wine, add enough stock to barely cover the rice, one-cup at a time. Simmer very slowly until all the stock has been absorbed. Continue adding the stock, one-cup at a time, allowing the stock to be absorbed slowly. Always wait for the previous cup to be absorbed first.
In the meantime, in a saucepan, heat the remaining 1-tablespoon Olive Oil and add the shallots cook for a couple minutes and add the shrimp, scallops and cook for 5 minutes and add the sherry wine and the Ricard. Cook 5 minutes longer. Add the green onions and the tomatoes. Cook until the seafood is cooked.
After all the stock has been absorbed into the rice, combine with the shrimp mixture. When all remaining liquid has been absorbed, adjust the seasonings with salt and pepper if needed and stir in the Parmesan cheese. Serve immediately.