In a pot, heat the oil and saute onion until translucent. Add carrots and garlic and saute for 1 more minute.
Add chopped tomatoes, tomato puree, sugar, spices and about 4 cups broth. Bring to boil and cook for about 15 minutes.
Add spaghetti and simmer until the pasta is tender, about 15 minutes. Stirr from time to time to prevent spaghetti from sticking. Add more broth or water while cooking to achieve consistency you like.