Heat a splash of oil in a large skillet over medium heat. Add the finely chopped onion and sauté for about 5 minutes, or until it becomes soft and translucent.

Stir in the ground beef, breaking it apart as it cooks, and brown until fully cooked, approximately 8–10 minutes.

With the ground beef browned, stir in the uncooked rice, tomato sauce, oregano, salt, and pepper. Add a splash of water, mix well, and let the mixture simmer for 10 minutes over low heat.

Preheat your oven to 180°C (350°F). While the oven heats, brush a large baking dish with melted butter or oil.

Take five sheets of phyllo dough and lay them one-by-one in the dish, brushing each layer generously with butter.

Once the filling has cooled slightly, spoon it into the prepared baking dish, spreading it evenly over the phyllo base.

Layer the remaining phyllo sheets on top of the filling, brushing each layer with melted butter, ensuring the edges are tucked in to secure the filling tightly inside.

Carefully place the assembled Kreatopita into the preheated oven and bake for 40–45 minutes.

Once done, remove it from the oven and allow it to rest for a few minutes before slicing.