Preheat oven to 450 degrees and line a large rimmed sheet pan with foil or parchment paper.
Arrange tomatoes cut side up on Sheetpan, potatoes, and shallots. Drizzle with olive oil, salt, pepper, thyme, and basil. Wrap garlic cloves in foil pack and place in the corner of the Sheetpan. Roast for 20-30 minutes, until tomatoes are caramelized.
Remove roasted tomatoes, potatoes, and garlic from the oven and add to a large stockpot or Dutch Oven along with chicken broth, whole peeled tomatoes, and tomato paste. Bring to a boil, reduce heat, and simmer for 15-20 minutes.
Meanwhile, make your parmesan croutons if making! Pre-heat oven to 400 degrees, and line 9 x 14 baking sheet with foil. Add olive oil, parmesan, salt, and garlic powder to a large bowl and stir to combine. Add cubed bread and toss to coat. Spread onto Sheetpan and bake for 10-13 minutes, until golden and crisp.
After soup has been simmering for 15-20 minutes, add fresh basil, and using an immersion blender (or transfer contents of the pot to a food processor or stand blender), blend until completely smooth. Stir in ghee or butter and adjust salt and pepper, and broth at this time.