Heat olive oil in a pan at medium low heat and add sliced onions. Stir the onions until they are coated with oil. Sprinkle a pinch of salt on the onions.
Stir the onions every few minutes or so. Cooking will take about 35-40 minutes. If the onions start to stick, add a little water, like a quarter of a cup or so. Add brown sugar or balsamic vinegar at the end of cooking time.
In a food processor, mix all ingredients until well blended.