Sauté onions: Heat 2 tablespoons of oil in a large skillet over medium heat. Add finely chopped onions and sauté for about 5 minutes until soft and translucent.

Brown ground beef: Add 500g ground beef and cook for 6-8 minutes, breaking it apart until browned and fully cooked.

Add rice and seasoning: Stir in 1 cup rinsed white rice, 1 cup tomato sauce, 1 teaspoon oregano, and season with salt and pepper. Pour in 1 cup water, bring to boil, then simmer for 10 minutes.

Prepare phyllo base: Preheat oven to 180°C (350°F). Brush a baking dish with melted butter or oil. Layer five sheets of phyllo dough, brushing melted butter between each sheet.

Assemble filling: Spoon the beef and rice mixture into the phyllo-lined dish and smooth the top with a spatula.

Top phyllo layers: Cover with another five sheets of phyllo dough, brushing melted butter between each layer and tucking edges down into the dish.

Bake: Place the assembled Kreatopita in the oven and bake for 40-45 minutes until golden-brown.

Let rest and serve: Remove from oven and let it rest for 10-15 minutes before slicing and serving warm.