Heat the oil, add the onions and carrots and cook without colour until softened. Add the beef to the pan and brown, stirring occasionally.
Add the flour and tomato puree and cook, stirring for 2 minutes. Stir in the Worcestershire sauce, thyme and stock and season. Bring to the boil, cover and simmer for 45 minutes. Do not let the mixture completely dry, the sauce should reduce a little though.
When cooked, add the chopped parsley, check the seasoning and put the meat in a dish.
Cook the potatoes and parsnips. Drain and mash, add the cheese and season. Top the mince with the mash and cook until topping in beginning to turn golden.