Good way to prepare it Maito!
The equitpment is not really expensive (50$ or so), but this takes a lot of space into the cupboard if it is big. We have a small one for 4 persons and we use it about 3 times each winter. During the meal I eat about 4 slices of cheese. It's convenient as I can adjust the speed of cooking and I dont' have to eat all at once until still hot.
The fun is sitting at the table, combine the ingredients and top the potatoes with the broiled cheese, about 10 minutes later the next slice of hot cheese.
Melt the cheese in the microwave in not real good because it is not broiled. Perhaps the cheepest way and more similar to the orignal would be a small non sticky pan that you can place into the oven to broil the cheese. Then pour the cheese over the potatoes. Place more cheese into the oven while eaten the first portion.
The original? A big piece of cheese placed near the flames of the open fire and scrab the melted hot cheese into the plates!