Mix together the meat, parsley, salt and pepper.
Turn meat mixture onto a floured board and flatten meat out to a rectangular shape.
Put ham slices on the meat, then spread on the mashed potatoes and lay the slices of Mozzarella on top.
Roll up like a jelly roll and press edges closed.
Heat two tablespoons of olive oil in a large frypan.
Place meat loaf in pan and pour remaining oil over the meat.
Cover frypan and simmer for about 15 minutes.
Mix tomato paste with the water and bay leaf.
Pour over the meat, cover and simmer for about one hour.
Remove loaf from frypan and allow to stand for about ten minutes before slicing.