Chop the top off of an entire head of garlic, drizzle with olive oil, wrap in tin foil, and bake at 400°F for 45 minutes
In a large pot over medium heat, add olive oil and once heated saute the onions, celery, and carrots until translucent. Salt as you go, around 5 minutes. Squeeze out the roasted garlic and thyme and saute another 2 minutes. Add the tomato paste and coat the vegetables. Saute another 3 minutes until it is rust colored.
Add the whole peeled tomatoes, chicken stock, salt and pepper and 4 basil leaves. Stir and bring to a simmer. Cover with a lid and simmer for 20 minutes.
Remove the lid and turn off the heat. With an immersion blender or a blender, blend the smooth until smooth. Stir in the heavy cream and serve, garnish with fresh basil.
