I originally created this salad dressing for fresh tomatillos, but it is also delicious with tomatoes, especially in the summer when ripe multi-coloured heirloom tomatoes appear in the markets. The dressing is a simple mixture of balsamic vinegar, agave syrup and cacao nibs. If you leave it to infuse for a few days, the cacao nibs release their complex flavour, like a vintage liqueur.