In a little oil in a large saucepan, caramelize the onion, ginger and sugar. Add the tomatoes, simmer about 10 minutes, add the broth, season with salt and pepper and simmer about 20 minutes more until tomatoes are soft. Add the basil and puree. Adjust seasonings. Serve hot or cold.
I used a hand blender, but a regular blender should work fine as well. Remember when pureeing hot items to only fill the blender jar about 1/3 full to allow for expansion or you'll have hot tomatoes all over you and your kitchen.