1. Heat the oil in a small frying pan over a medium fire. Add the onion and thyme and cook for 15-20 minutes, stirring occasionally.
2. Add the sugar and cook for another 3 minutes, stirring continuously.
3. Add the balsamic vinegar and half a cup of cold water. Simmer and stir the mixture for 5 minutes until it blends well.
Serve with steaks, sausages or burgers.