Place the cut potatoes into a large pot with water and 1 teaspoon of salt. Bring to a boil and cook until tender, about 15 minutes. Drain and set aside.

In a frying pan over medium heat, add vegetable oil. Once hot, add the chopped onion and sauté for about 3 minutes until softened and fragrant.

Add the minced meat to the pan with onions and cook for about 5 minutes, breaking it apart as it cooks. You want it nicely browned.

Stir in the bell pepper, tomato paste, water, salt, dried garlic or paprika, oregano, and black pepper. Cook for another 2-3 minutes to combine flavors.

In your baking dish, evenly layer half of the cooked potatoes, followed by the meat mixture, and then half of the cheese slices. Repeat with another layer of potatoes and meat, topping with the remaining cheese slices.

In a bowl, whisk together the eggs, milk, 1 teaspoon salt, and 1 teaspoon oregano until fully combined. Pour this mixture evenly over the layered ingredients.

Sprinkle the grated cheese over the top of the casserole.

Preheat your oven to 350°F (180°C) and bake for 15-20 minutes, or until the cheese is melted and bubbly.

Remove from the oven and let it cool slightly. Garnish with chopped green onions before serving.