This is a good one for those days when you don't have time to make a full-on shepherd's pie. It is simple yet delicious and is beautifully rich and full of flavour. I've included some pictures but they don't look much and certainly don't do the flavour justice. But hey, this is a casserole and since when did they ever look that good?! I have only made this in the oven but there's no reason you can't make it in a crockpot. I will definitely be trying it that way when the weather cools and my crockpot comes out again! I usually make this with about a quarter pint extra gravy cos we like a lot of gravy in our stews/casseroles, but I imagine most people would prefer it a little less runny so I have adjusted the recipe accordingly. This serves up beautifully with mash and cabbage/green beans.