Preheat your oven to 400°F (200°C).

Scrub the potatoes, prick them with a fork, and bake directly on the oven rack for 45–60 minutes until a skewer slides in easily.

While the potatoes roast, heat a skillet over medium heat and sauté the chopped onion until soft, about 4–5 minutes. Add the minced garlic and cook for 30 seconds.

Add the ground beef or lamb to the skillet, breaking it up and cooking until browned and no pink remains. Drain excess fat if needed.

Stir in the frozen mixed vegetables, beef broth, Worcestershire sauce, salt, and pepper. Reduce the heat and simmer for about 10 minutes until the mixture thickens slightly. Taste and adjust seasoning.

Remove the potatoes from the oven. Cut each in half lengthwise and scoop out most of the flesh into a bowl, leaving a thin shell.

Mash the scooped potato with butter and milk until smooth and creamy; season with salt and pepper.

Spoon the meat-and-veg mixture evenly into the potato skins.

Pipe or spoon the mashed potato over the filling, smoothing it or creating peaks as desired. Sprinkle each with shredded cheddar.

Return the filled potatoes to the oven for 10–15 minutes, or under a broiler for 2–4 minutes, until the cheese is melted and bubbly, and edges are golden. Let rest a few minutes, then serve.