In a blender, add tomatoes, onion, cumin, and salt. pepper and 2 cups of broth. Blend well and set aside.
Add the noodles to a saucepan with a tablespoon of oil. Cook the noodles over medium heat for 3-5 minutes or until some of them are turning a light brown. Add the tomato-onion mixture to the saucepan and combine it well with the noodles.
Add remaining vegetable broth, bring the soup to a boil and then reduce heat to a simmer and let it cook for 15-20 minutes, or until the noodles are cooked through. Add Mexican blend cheese, and cook for 5 minutes more.