Boil the potatoes in lightly salted water. Rinse the boiled potatoes with cold water, peel them, and slice them into ½-inch-thick slices. Wash the tomatoes, remove their stalks, and cut them into ½-inch-thick slices.
Heat some olive oil in a pan over medium heat, add the ground beef, and season with salt and pepper. Once the meat has cooked through, remove the pan from the heat.
Grease a casserole dish and layer the ingredients in the following order: potato slices, ground beef, sour cream, oregano, tomato slices, shredded mozzarella cheese.
Transfer the casserole dish to a preheated oven and cook at 350°F for 15 minutes. Garnish the meat & potato casserole with fresh oregano leaves before serving.
