1. Remove onion peel. Rinse. Cut onion in half lengthwise. Then slice. 2. In a pan, heat oil, add the onions, fry on medium heat for 10-15 minutes, or until translucent and softened. 3. Add the balsamic vinegar, honey, and salt. Cook for 2 to 3 minutes or until the mixture is syrupy. Season with pepper. 4. Cook wors till done the way you prefer. I prefer it just done, still juicy. 5. Slit the roll on the top, place a slice of cheese in. Then place a cut piece of wors. 6. Squirt on tomato sauce, caramelized onions and sliced baby plum tomatoes. 7. Sprinkle parmesan cheese if using. 8. Bake in preheated oven at 180 degC till the outside of rolls crisp up. 9. When done, if using, place on stick chips and serve warm.