Place one tablespoon of oil in a skillet or saucepot and heat over medium. Add chopped onions and continue cooking, stirring frequently, over medium heat until brown and caramelized (about five minutes or so). Pour in cider vinegar and stir well to loosen the coating on the bottom of the pan.
Pour the entire contents of the skillet into the blender and add the remaining oil along with all other ingredients. Blend on high for two minutes, until well blended and emulsified.
Refrigerate for several hours before serving over your favorite salad. Recommendation: dark greens with pecans, chopped apples, and dried cranberries.
