Heat a sauté pan and add enough olive oil to almost cover the bottom. Sauté onions and garlic over medium heat until the onions are tender. Add basil and simmer for one minute. Remove the mixture and place into a pot.
Add the tomatoes, mushrooms, chicken broth, thyme and salt to the onion mixture and simmer on medium heat. Add a bit more olive oil to the pan and heat to medium high. When oil is hot, add the scallops. Very lightly brown on each side. Remove the scallops and add them to the pot.
Add the shrimp to the hot pan and stir-fry for 2 minutes. Remove the shrimp and add to pot. Add the cooking wine, chicken broth and the Worcestershire sauce to the hot pan and stir to deglaze. Simmer for 2 minutes. Add the wine mixture to the pot. Add the sugar to the pot (more or less to taste depending on the acidity of the tomatoes).
To thicken sauce (if desired), add cornstarch to 1/4 cup of water and dissolve. Slowly stir into the mixture. Stir and simmer 4 minutes. Serve over a bed of rice with crusty bread to soak up the gravy.