How to cook
Mash the boiled potatoes with a little butter and divide it into 2 parts.
Smear a nonstick oven dish with butter and pour half the mashed potatoes into it, arrange raw baby spinach to cover it. Pour the pork with the onions on top, grate cheese, put spinach again and finish off with the rest of the mashed potatoes.
Even it out well and put in a preheated oven. Once it bakes a bit, grate on some more cheese and return to the oven to brown.