In a blender or food processor, drop in the tofu and blend until smooth and creamy. Set aside. (should make approximately 2/3 cup).
In a large saucepan, melt 1 tablespoon of the butter in 1 tablespoon of the olive oil. Add the sliced onion and smashed garlic and cook over moderate heat, stirring occasionally, until softened, about 5 minutes. Add the tomatoes and their juice, the water, blended tofu, sugar, crushed red pepper, celery seed and oregano and season with salt and pepper. Bring the soup to a boil over high heat, breaking up the tomatoes with the back of a spoon. Reduce the heat to moderate and simmer for 10 minutes.
Working in batches, transfer the tomato soup to a blender and puree until smooth. Return the soup to a clean pot and rewarm the soup if necessary. Season the soup with salt and pepper. Ladle the soup into bowls and serve with the croutons.