Steam (or boil) the potatoes until they are fully tender, about 20-30 minutes depending on the size and quality of the potato. As soon as they are cool enough to handle, peel the potatoes and run them through a food mill or potato ricer into a large bowl, as if you were making mashed potatoes. Add the butter, grated cheese, seasonings and whole eggs. You can also add, as pictured, the cured meats to this mixture.

Mix everything very well until the butter is melted and the other ingredients well incorporated. If the mixture is too stiff to work with, add a bit of milk, a few drops at a time, until you have the texture you want.

Grease the bottom and sides of an 8" cake pan (or casserole) with the butter and line completely it with breadcrumbs.

Spread out half the mashed potato mixture on the bottom of the pan, then arrange the cheese and (if you have not added them to the potato mixture) the cured meats on top.

Add the other half of the mashed potato mixture on top of the filling and even it out so that the surface is nice and flat. Top the whole thing with more breadcrumbs and a few nobs of butter here and there.

Bake in a moderate oven (180C/350F) for about 30-45 minutes, until the gattò is cooked through and golden brown. (If the top is not quite browned enough, raise the heat for a few minutes before removing from the oven.)

Let the gattò cool off for a good 20 minutes or so before serving. Unmold the gattò if you baked it in a cake pan, and serve it just like a cake. If you baked it in a casserole, just bring it to the table and serve.