Crush tomatoes with your hands in a large bowl.
In a large pot, heat 3 tablespoons of olive oil over medium high heat. Add onion, shallot, garlic, and cook until they begin to soften - you do not want them to colour. Stir in the tomatoes and two-thirds of the basil leaves and mix to a boil. Add the chicken stock and return to a boil. Season with salt and pepper, reduce heat to low, and simmer, cover for about 40 mins.
For the croutons, in a sauté pan, heat 1 tablespoons of the olive oil over medium heat. Work batches, fry the bread cubes until golden brown. When they are all done, drizzle them with the remaining 1 teaspoon olive oil.
Serve the finished soup topped with the croutons and garnish with basil.