Preheat oven to 400°F (200°C).

Place halved tomatoes on a large baking sheet and coat with olive oil, garlic pepper, Italian seasoning and parmesan cheese. Bake for 45 minutes. Remove from oven and set aside.

In a large pot or Instant Pot, add olive oil, onions, garlic, butter and red pepper flakes and cook until onions are fragrant and softened, about 6 minutes.

Add canned tomatoes, basil, thyme, and chicken broth. Add the oven-roasted tomatoes, including the liquid on the baking sheet. Bring to a boil and simmer uncovered for 40 minutes.

Using an immersion blender, blend the soup until you have reached your desired consistency.

Serve warm topped with grilled cheese croutons, crispy croutons and Parmesan cheese.