Preheat the oven to 400 degrees.
Wash and cut your tomatoes into fours; set aside as you chop. Peel the garlic cloves and chop the onions also.
Place the cut tomatoes onto the cast iron pan along with the garlic cloves. Mix 1/3 cup of the Olive Oil with the tomatoes and garlic cloves evenly (you can use your hands for this, just make sure they're clean!). Once the oven is preheated place the tomatoes and garlic in the oven to roast for 1 hour.
About 15 minutes until the tomatoes and garlic are done roasting, start heating your dutch oven on the stove top on medium heat. Add in the 1 tbsp of Olive Oil and heat until the oil is hot.
Add in the chopped onions to the dutch oven. Once fragrant, add in the dried basil, oregano, garlic powder, and fresh thyme. Mix for about 1 minute until fragrant.
Next, add in the balsamic vinegar. Keep cooking the balsamic vinegar until it stops bubbling. The vinegar will also reduce by half once it is cooked through. Add in the bone broth and heat until it starts boiling.
By this time, the tomatoes and garlic should be done so you will pull them out of the oven, and shut the oven off. Put them off to the side on a burner to cool down a bit.
Once the bone broth is boiling, scoop out the tomatoes and garlic and place them into the dutch oven with everything else. Use an immersion blender to finely blend the everything. Even when you think it is finely blended, blend it some more!
You will then add in the sun-dried tomatoes, blending them into the soup. Then slowly add in the heavy cream, blending it into the soup. Top it off with some salt and pepper.
Pair it with a side salad and/or a grilled cheese and you have the best Tuscan Tomato Soup!