Heat oil in skillet, add onion and beef and cook until meat is lightly browned, stirring to keep meat crumbly.
Stir in tomato sauce, wine, seasonings, garlic salt, sugar and salt and pepper to taste.
Cover and simmer for 1 hour, stirring occasionally.
Wash zucchini, trim off ends and cook whole in boiling water, salted.
Boil 10 to 15 min or until just tender.
Drain and when cool enough to handle, cut in halves lengthwise.
Arrange in a single layer, cut-side up, in a greased and shallow baking dish.
Pour sauce over zucchini and bake at 350 degrees for 45 min.
Sprinkle with Parmesan cheese.