- 1 tablespoon olive oil, or as needed
- 2 onions, coarsely chopped
- 1 cup water
- 1/4 cup balsamic vinegar
- 1/4 cup brown sugar
- Heat olive oil in a saucepan over medium-high heat. Saute onion in hot oil until soft and caramelized, 10 to 12 minutes. Add water, balsamic vinegar, and brown sugar; stir until sugar is dissolved and mixture is simmering. Reduce heat to low and cook until mixture thickens and reaches desired consistency, about 30 minutes.