Along with the grated beetroot and carrot, I have added a bit of spice for interest, but not so much that it overpowers the lamb. There is something very comforting about creamy mashed potato baked in the oven. The butter and onion add to the texture and flavour and the aroma is all too inviting. I serve the shepherd's pie with my favourite homemade tomato relish, but I confess the tomato sauce is seen on the table too!