1. Heat oven to 425 degrees Fahrenheit.
2. In a roasting pan, coat tomatoes with 1 tablespoon olive oil, salt and pepper
3. Roast for 25-30 minutes or until tops are browned.
4. In a large soup pot heat the other 2 tablespoons of olive oil.
5. Add onions and saute until slightly browned.
6. Add bell pepper and roasted tomatoes and saute for another five minutes.
7. Add tomato sauce, water, garlic powder, salt and pepper and bring to a boil. Lower heat and simmer for 20-30 minutes.
8. Blend soup with immersion blender.