- Peel the onion and then cut in half crosswise.
- Preheat the oven at a temperature of 400°F. Spray the baking sheet with the cooking oil. Take a bowl, mix together the onion, garlic and tomatoes with 1 tbsp of the oil; toss well to combine.
- Seasoning, and then put the mixture on a baking sheet and spread over the sheet evenly. Put the baking sheet in an oven and then roast until the vegetables are caramelized, for about 30 minutes. Leave to cool.
- Peel the tomatoes and then remove the seeds of the tomatoes; cut the ends off the onion; peel the garlic. Blend them in a blender together with the 1 cup of vegetable soup and the remaining oil, until desired thickness.
- Ladle the mixture to a large heavy pot, and then put the remaining of the soup, tomato paste, tomato juice, Worcestershire sauce and basil. Heat, bring to simmer, stirring.
- Transfer to the soup bowls. Garnish 'Roasted Tomato Soup' with the corn and serve.