Preheat your oven to 400°F and line a baking sheet with parchment paper.
Place the halved Roma tomatoes and peeled garlic cloves on the sheet, drizzle with olive oil, and sprinkle with sea salt and black pepper.
Roast for 25 to 30 minutes until the tomatoes are blistered and slightly charred.
While the tomatoes roast, sauté the diced yellow onion in a large pot over medium heat until translucent and soft.
Add the roasted tomatoes, garlic, and any juices from the pan into the pot along with the chicken bone broth.
Simmer the mixture for 10 minutes to allow the flavors to meld.
Use an immersion blender to process the soup until it reaches a smooth, velvety consistency.
Stir in the shredded cooked chicken breast and Greek yogurt, heating through for another 2 minutes.
Remove from heat, stir in the fresh chopped basil, and serve immediately.