Chopped basil and freshly grated Parmesan cheesefor garnish, optional
Preheat oven to 400 degrees F. Line a large baking sheet with parchment paper. Place the halved tomatoes and garlic cloves on the baking sheet and drizzle with 2 tablespoons of the olive oil. Sprinkle with oregano, salt, and black pepper.
Place the baking sheet in the oven and roast for 45 minutes until tomatoes are soft and juicy.
Remove the roasted garlic from the peels give them a rough chop. Set aside.
In a large stockpot, heat the remaining 2 tablespoons of olive oil over medium heat. Add the onion and cook until tender, about 3 to 5 minutes. Stir in the garlic and red pepper flakes. Add the canned tomatoes, 1 1/2 cups of vegetable broth, basil, and thyme. Stir in the oven roasted tomatoes. Let simmer on low for 30 minutes.
Use an immersion blender to puree the soup in the stockpot until smooth. If the soup is too thick for your taste, you can add additional broth. If you don’t have an immersion blender, let the soup cool for a few minutes and then carefully transfer to a food processor or blender to blend. Season with salt and pepper, to taste.
Ladle the soup into bowls and garnish with fresh basil and Parmesan cheese, if desired. Serve warm.
Be careful when transferring hot soup to a blender or food processor. You may want to wait until it is at room temperature to blend.