- In a saucepan, caramelize the onions in the oil for 15 to 20 minutes.
- Add the balsamic vinegar, honey, and salt. Cook for 2 to 3 minutes or until the mixture is syrupy. Season with pepper. Divide among four 125 ml (½ cup) clean jars. Close and let cool. Refrigerate for at least 2 hours before using. Will keep for about 1 month in the refrigerator.
Serve with steak, duck, savoury pies, or burgers.