Preheat your oven to 375°F (190°C).

Slice the tops off the tomatoes and set them aside. Carefully scoop out the pulp and seeds with a spoon, leaving a sturdy shell. Chop the scooped pulp roughly.

In a large skillet, heat the olive oil over medium heat. Add the chopped onion and cook until softened, about 5 minutes.

Add the ground lamb and garlic to the skillet. Cook until the lamb is browned, breaking it up with a wooden spoon.

Stir in the reserved chopped tomato pulp, dried oregano, salt, and pepper. Simmer for 3-4 minutes to reduce the liquid slightly.

Remove the skillet from heat. Stir in the cooked rice, fresh mint, and parsley until well combined.

Place the hollowed tomato shells in a baking dish. Generously fill each tomato with the lamb and rice mixture.

Top the stuffed tomatoes with the crumbled feta cheese and place the reserved tomato lids on top.

Bake in the preheated oven for 30-35 minutes, or until the tomatoes are tender and the filling is hot.

Let cool for 5 minutes before serving to allow the flavors to settle.