This is the most popular dish in our family. I always buy delicious ground pork from the Seikatsu Club (a farm-to-table food coop). The seasoning is simple to highlight the natural flavors of the ingredients.
Make mashed potatoes. Mash boiled potatoes, add butter and milk and mix. When it is your desired consistency, season with salt and pepper.
Sauté the ground pork and finely chopped onions together in a frying pan. When they are cooked through, season with salt and pepper. (Onions are often grown with a lot of pesticides! Use reduced-pesticides or organically grown ones.)
Layer the meat and potatoes in a gratin or shallow baking dish in that order. Top with cheese, and bake in an oven or toaster oven until the cheese has melted. (I didn't have any pizza cheese so I used sliced cheese.
When I used a variety of potato called "The Awakening of the Incas," my family all murmured, "It's soo good!"
It's delicious reheated in the microwave the next day.
Addendum: If you keep the removed fat in the refrigerator and use it for stir-fries, you can add a lot of umami! (Taking all the fat off will make the meat less tasty, so leave a little.)
Story Behind this Recipe
There are several recipes like this. Ones using lamb or beef, or shepherd's pie and so on. I made my version using potatoes I had on hand and Sangen Pork from Hirata Farm via the Seikatsu Club. Because the recipe is so simple, the flavors of the ingredients really shine!
If you season both the pork and the potatoes enough that you can eat either one on its own, the seasoning will be just right.