Preheat your oven to 375°F (190°C) and lightly grease a 9x13 inch baking dish with a little olive oil.

Slice the tops off the tomatoes and carefully scoop out the seeds and pulp with a spoon, leaving a sturdy shell about half an inch thick.

Roughly chop the scooped-out tomato pulp and set it aside in a small bowl to use in the filling later.

Heat the olive oil in a large skillet over medium heat, then add the chopped onion and cook for 3-4 minutes until softened.

Add the ground lamb and minced garlic to the skillet, breaking up the meat with a wooden spoon, and cook until the lamb is browned and no longer pink.

Stir in the reserved chopped tomato pulp, cooked rice, dried oregano, salt, and pepper, letting the mixture simmer for 2-3 minutes to meld the flavors.

Remove the skillet from the heat and fold in the fresh chopped mint and crumbled feta cheese.

Spoon the lamb and rice mixture generously into each hollowed tomato shell, packing it down gently.

Place the stuffed tomatoes into the prepared baking dish and bake for 30 to 35 minutes, or until the tomatoes are tender and the skins begin to wrinkle slightly.

Remove from the oven and let them cool for 5 minutes before serving warm, garnished with extra fresh mint if desired.