1. In a saucepan, cook the onion in the oil until soft but not brown. Add the tomatoes, carrots, salt, pepper and sugar.
2. Cover and cook over low heat for 5 minutes. Remove the cover and cook over low heat, stirring often, for another 5 minutes, or until the carrots are tender and the tomatoes are cooked down to a sauce.
3. Stir in the parsley. Mix the butter with the cooked elbows. Stir in the carrot mixture and serve.