In a medium pot, heat olive oil over medium heat. Add the onion and garlic and cook until tender, roughly 4 minutes.
Add in the tomatoes, broth, basil, salt and pepper. Bring to a boil, then reduce heat and simmer for 10-15 minutes.
Meanwhile, you can make the cheesy bread dippers. Heat the oven to a broil and line a baking sheet with tin foil. Butter or oil one side of the bread and place it on the baking sheet, broil until golden brown - roughly 4 minutes. Flip the bread and sprinkle with the cheese and Italian spice mix, place back under the broiler and heat until golden brown. Let cool and then cut into 2-inch strips.
When soup is done, add in the yogurt and using a hand immersion blender or a blender, blend the soup until smooth and creamy.
Let cool slightly and then serve the soup with the cheesy bread dippers.