Peel the onions and cut them into thin rings. Heat the remaining oil in a pan. Fry the onion rings until light brown, remove them, and drain thoroughly on plenty of kitchen paper.
Step 5 of 5
6 Finally, thicken the gravy with small pieces of cold butter. Don't let it boil. Then add the meat, along with any accumulated juices, to the gravy and heat through briefly. Scatter the fried onions over the top before serving.