tomato salad with onion dressing

2 large onions, cut in quarters and thinly sliced
½ cup olive oil

3 tbsp faerie's grey sea salt with herbes de provençe
6 tbsp balsamic vinegar

• Over very low heat, combine sliced onions with olive oil and carmelize.
  The secret to properly carmelized onions is to leave the kitchen, returning about every
  15 minutes to stir.   This will take about 90 minutes.  Do not be tempted to turn up heat.

• After onions are carmelized, remove from heat and allow to cool.
• Add vinegar and herbed sea salt to dressing and mix well.
• Mix dressing with tomatoes and let sit at least one hour at room temperature prior to serving.