Heat oil in medium-size saucepan over low heat. Add onion and garlic; cook, stirring occasionally, 20 minutes or until onion is softened, making sure garlic doesn't burn. Add tomatoes, parsley, basil, salt and pepper. Bring to boiling; reduce heat; simmer, uncovered, 20 minutes.
Cook spaghetti in large pot of lightly salted boiling water until firm but tender. Drain. Serve sauce over spaghetti. Makes 6 servings.