Preheat oven to 350F.
Heat a large pot over medium-high heat with 2 tablespoons of EVOO, 2 turns of the pan. Season the chicken with salt and pepper and add to pot. Cook for about 3-4 minutes, or until just cooked through. Remove from the pot and set aside. Add the other 2 tablespoons of EVOO along with the chopped garlic, onions and red pepper flakes.
Cook for about 3-4 minutes. Add tomatoes and the stock, bring to a simmer and cook for about 3-4 minutes. Add chicken back to the pot and cook for 2-3 minutes. Add the chopped basil and stir to combine.
While the soup is cooking, drizzle the sliced bread with some EVOO and season with salt and pepper. Place on a baking sheet and toast until lightly golden, about 3-4 minutes. Remove from the oven, rub each piece with the garlic clove and top with parmesan cheese. Place back in the oven for 1-2 minutes.
Serve soup topped with 2 pieces of parmesan toast or, if you prefer, put the bread on the bottom and the soup on top.