Caramelised Red onion beef quarter pounders

beef 81.0% , red onion 8.0% , rice flour 7.9% , muscovado 4.7% , chives 3.2% , sugar 2.2% , cider vinegar 1.7% , onion 1.3% , dehydrated onion 0.9% , sea salt 0.7% , spice 0.6% , salt 0.5% , spirit vinegar 0.5% , rapeseed oil 0.3% , corn flour 0.2% , yeast powder 0.2% , yeast extract 0.1% , Preservative 0.1% , garlic 0.1% , dextrose 0.0% , onion oil 0.0%