To make the Parmesan crumble, mix the softened butter with flour, the Gruyère and the grated Parmesan to obtain a consistent paste and leave to one side.

Next, arrange the Potato Mash on the bottom of a dish and add the finely sliced cured ham before sprinkling the crumble mix over the top.sistent paste and leave to one side.

Leave to cook for around 20 minutes in an oven pre-heated to 180°C.