Preheat the oven to 375 degrees.

In a large mixing bowl, combine tomatoes, carrots, celery, garlic cloves, and olive oil.  Combine well so that everything is coated in olive oil, then spread onto a baking sheet.

Roast the mixture for about an hour and a half (1.5 hours) stirring occasionally.

Transfer the roasted vegetables into a blender and blend until creamy.  Or use an immersion blender,  if you prefer.

In a large pot, combine the blended mixture, stock, and seasoning then bring to a boil.  Cook on low heat for 20 minutes.

Remove from heat, add salt and pepper to taste.

Serve hot, top with freshly grated parmesan cheese and basil leaves.