Prepare and bake or boil potatoes
Preheat oven to about 200 °C (400 °F) if baking. Wash the potatoes well. You can bake whole potatoes until tender (about 45–60 minutes depending on size) or boil until fork‑tender if preferred. Allow potatoes to cool slightly.

Slice and scoop out potato flesh
Once potatoes are cool enough to handle, slice them lengthwise (or crosswise if using larger ones) and carefully scoop out the insides, leaving a shell about ½‑inch thick. Reserve the scooped potato flesh for mixing into filling.

Make the ground beef filling
In a skillet over medium heat, melt a bit of butter or oil; sauté diced onion until translucent. Add minced garlic and cook for 1 minute until fragrant. Add ground beef, breaking it up, and cook until browned. Season with salt, sweet paprika, and black pepper. Stir in tomato sauce and let it simmer for a few minutes. Optionally, stir in the reserved potato flesh into the meat mixture to create a creamier texture and stretch filling.

Fill the potato shells
Butter the potato shells lightly if desired. Spoon the meat filling into each shell generously. Top with shredded or grated mozzarella cheese.

Bake to finish
Place the stuffed potatoes on a baking tray. Bake in the oven at about 200 °C (400 °F) until the cheese is melted and bubbly and the tops are lightly golden (approx. 10‑15 minutes).

Garnish and serve
Remove from oven, sprinkle freshly chopped parsley over the top. Let rest a few minutes before serving. Serve hot.