This one occurred to us after "Burns Night" as a decent way to use various leftovers when we realised that a whole Haggis was a bit big for a small household or a single person to tackle in one go...
1) Take the leftover cooked Haggis you didn't finish on Burns Night, Saint Andrews Day, or whenever you happen to like to eat Haggis, and put it in the bottom of an oven-proof dish.
2) Take whatever leftover casserole you might have hanging about the place (since we're all on budgets, I just know we'll all be in the habit of freezing leftovers for future use); pour it on top of the Haggis layer.
NB: this idea doesn't work as well with the Haggis above the casserole - having the moist thing on top stops the Haggis drying out.
3) Mash up leftover boiled Tatties and Neeps (that's Potatoes and Swedes to us Sassenachs; and remember that what the Scots call "Swedes" the English tend to call "Turnips" and vice versa - in this recipe, I mean "English Swedes") you had with the Haggis yesterday (if you were being "authentic") and spread the mash as evenly as you can on top of the meaty mix. Try not to leave gaps at the sides of the mash or else the meaty mix underneath will try to escape all over the inside of your oven while it's cooking.
4) Heat through in a hottish oven (make sure it's piping hot in the middle, but you don't need to be precise - all the ingredients are cooked already as they're all leftovers). If you don't cover the dish, the mash topping should even brown.
5) Serve with green veg.
NB: never re-freeze food that has previously been frozen; if you're not sure something's safe to keep and use as leftovers, don't take the risk. In Short - Don't Blame Me!
Edited once, at 12:11 on 28 Jan 2009