Start by cooking the potatoes, either steamed or in the microwave. Wash them very well since you'll cook them with the skin on. To prevent them from bursting, poke them with a knife.

When the potatoes are tender and a knife goes in easily, remove them and let them cool. Once you can handle them without burning yourself, slice them into rounds that aren't too thin and remove the skins.

Slice the onion into thin strips, cut the bell pepper into strips, and slice the tomatoes. Set aside.

Season the bottom of an oven-safe baking dish with salt, pepper, and a drizzle of olive oil.

Arrange the potato slices on the bottom. Don't worry if they break apart—just make sure the bottom is well covered.

Add a layer of bell pepper strips on top, then a layer of onion. Drizzle with olive oil and sprinkle with salt.

Preheat the oven to 400°F (200°C), using both top and bottom heat if possible.

On top of the potatoes, peppers, and onions, arrange the seasoned pork loin pieces. I used two per person, placed crosswise, but arrange them however works best for you.

Place a couple of cheese slices on top of the pork loin and add a generous handful of spinach to cover the dish well.

Add the tomato slices and, if you like, two more slices of cheese (some wanted cheese, others didn't).

Drizzle with olive oil and sprinkle oregano to taste.

Bake for about 15–20 minutes. Serve hot and enjoy!