Butter basted breast joint with pork sage and onion stuffing

british chicken breast 70.0% , pork 13.0% , onion 6.0% , water 4.0% , salted butter 2.0% , rice flour 1.3% , parsley 1.3% , chickpea flour 1.3% , salt 0.6% , sage 0.5% , corn flour 0.1% , chicken 0.0% , sugar 0.0% , thyme 0.0% , black pepper 0.0% , Preservative 0.0% , onion 0.0% , sunflower oil 0.0% , shiitake 0.0% , seaweed 0.0%