Preheat oven to 400°F (200°C). Scrub potatoes, pierce several times with a fork, and bake directly on the oven rack for 45–60 minutes until a skewer slides in easily.

While potatoes roast, heat a skillet over medium heat with a tablespoon of oil. Sauté the chopped onion for 4–5 minutes until soft. Add minced garlic and cook for 30 seconds more.

Add the ground beef or lamb. Break it up and brown until no pink remains. If there’s excess fat, drain most but leave a little for flavor.

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

Remove potatoes from the oven and let cool briefly. Cut each in half lengthwise and scoop out most of the flesh into a bowl, leaving a thin shell (about 1/4 inch) so skins stay sturdy.

Mash the scooped potato with 2–3 tablespoons of butter and 2–4 tablespoons of 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 or making peaks. Sprinkle shredded cheddar over each.

Return to the oven for 10–15 minutes until everything is hot and the cheese is melted and bubbling. For browned peaks, switch to broiler for 2–4 minutes — watch closely to avoid burning. Let rest a few minutes before serving.