Sauté the sliced onions in the Lemon oil until slightly transparent. Cover with balsamic and reduce until the onions caramelize.
You can use almost any sweet balsamic vinegar for this recipe. For example, try Peach Balsamic in the fall and Strawberry Balsamic in the spring. 18 Year Old Balsamics are good year-round!
This is a great topping for sandwiches, hot dogs, or hamburgers. To impress your guests with a great appetizers, spread the caramelized onions on a pastry and slice.