This is a simple way to transform any leftovers into a totally different meal. Dishes like this are incredibly versatile, so use whatever you have on hand. It’s a great way to use up any sad looking vegetables in the bottom of your fridge. I added half a leek and some old parsley to the filling, and some wrinkly parsnip and leftover cauliflower to the mashed potato topping. If there isn’t much pork left you can always bulk it out with a can of lentils or beans.