The potato gateu (or gattò) is a typical Neapolitan dish. A real comfort food!
I propose my own version, lighter than the original one.
1 kg potatoes (2.2 Lbs.)
200 ml milk (6.5 oz)
50 gr butter (almost 2 oz.)
150 gr ham (5 oz.)
80 gr grated Parmesan cheese (almost 3 oz)
salt, pepper, nutmeg, breadcrumbs
Boil the potatoes, peel and mash them. Then prepare a puree, putting the mashed potatoes, the milk, three pinches of salt, and the butter. Let cool. Meanwhile, whisk the egg white. Then add to the puree, while mixing, the egg yolk, the cooked ham, cut into thin strips, a pinch of nutmeg and one of pepper; at the end, the whipped egg white until stiff.
And now set up the pie: butter a baking pan with high sides and sprinkle with bread crumbs. Put half of the mashed potatoes, then the diced mozzarella, then the second half of the mashed potatoes. Ultimate by sprinkling grated Parmesan cheese, and butter. Bake at 180 °C for 40 minutes, until the surface is brown.
Better if you eat it warm.