GNOCCHI: When mashed potato has cooled slightly, add the lightly beaten egg and gradually add the flour.
To make gnocchi, knead the potato mixture into a ball and separate into 6 equal portions. Roll each portion into a 1/2-inch thick roll and cut into small pieces. Cook in batches in boiling salted water for 10 to 15 minutes. When the gnocchi float to the surface they are ready.
SAUCE: While the gnocchi is cooking, sauté onion and garlic in oil until tender. Stir in wine, tomatoes with juice, tomato paste, brown sugar and basil; bring to a boil. Reduce heat and simmer for 5 minutes. Serve sauce over cooked gnocchi.
To serve, sprinkle with freshly grated parmesan cheese, if desired.