Add the remaining oil and the onion to the pan. Cook stirring, for 3-4 minutes or until softened. Add the garlic, ginger, chilli, turmeric, mustard seeds, cumin and coriander. Cook, stirring, for 2 minutes or until aromatic. Add the coconut cream and the chicken. Bring to the boil. Partially cover and reduce heat to low. Simmer for 20 minutes or until the chicken is tender.