Preheat oven to 180C/160C Fan/Gas 4. Fry onions in oil or fat for 10 minutes until soft, then place them on an ovenproof dish.
Add the meat, the carrots and any leftover vegetables. Finish off with a layer of sliced potatoes, seasoning each layer as you go.
Pour in hot stock and bake for 1 hour until everything is tender.