Creating Greek Stuffed Onions involves a few simple steps that will lead to an incredible meal. Follow these instructions carefully:

1. Preheat the Oven: Start by preheating your oven to 375°F (190°C), preparing it for roasting the stuffed onions.
2. Prepare the Onions: Cut the tops off the large onions and hollow them out, keeping the shells intact. Reserve the onion flesh for the filling.
3. Sauté the Filling: In a skillet, heat the olive oil over medium heat. Add the diced small onion and sauté until translucent. Then add the minced garlic and cook for another minute.
4. Mix Ingredients: In a large bowl, combine the cooked rice, ground beef (or lamb), sautéed onions, oregano, mint, salt, and pepper. Then mix in the diced tomatoes, tomato paste, and chopped parsley. Optional: Fold in the crumbled feta cheese for an extra flavor boost.
5. Stuff the Onions: Carefully stuff the hollowed-out onions with the filling mixture, pressing down gently to ensure they are well filled.
6. Arrange in Baking Dish: Place the stuffed onions upright in a baking dish. Squeeze lemon juice over them for added flavor.
7. Bake: Add a small amount of water or broth to the bottom of the dish to keep the onions moist. Cover with foil and bake in the preheated oven for about 30 minutes. Then remove the foil and bake for an additional 15-20 minutes or until the onions are tender and the filling is golden.
8. Serve: Once baked, remove from the oven and let them rest for a few minutes before serving.

These concise steps will guide you in crafting remarkably flavorful Greek Stuffed Onions that are sure to impress.