Prep the veg by peeling and finely dicing the onions, and peeling the potatoes and cutting into chunks.
Trim the visible fat from the lamb steaks and cut them into chunks. Sprinkle the corn flour over the lamb chunks and season them with salt and pepper.
I rendered down some of the trimmed fat in my casserole dish to release fat for cooking, but you could use olive oil. Fry the lamb in batches to brown it all over and remove them to a bowl.
Now add a little bit of stock to your pan and use a wooden spatula to scrape up the browning on the bottom of the pan, then add in your onions with some more oil to cook them gently for 5 minutes or so.
Add the browned lamb and any reserved juices back to the casserole pot. Stir the mint sauce and tomato purée into the remaining hot stock, then add this into the casserole. Finally put the potatoes in the top. Put the lid on then place in the oven for two hours at 180 C.
Boil your peas just before serving and sprinkle them on the top to finish the dish and add a bit of colour!
