Prepare the potatoes by peeling and cutting the Russet potatoes into quarters. Place them in a large pot of cold, salted water and bring to a boil. Cook until fork-tender, about 15-20 minutes. Drain and mash until smooth; season with butter, salt, and pepper.

In a large skillet, heat olive oil over medium heat. Add ground beef and cook until browned, about 8-10 minutes. Drain excess fat, add garlic powder, salt, and pepper. Stir in cheese until melted.

Scoop mashed potatoes into hands and form a bowl shape, then spoon beef filling into the center. Press mashed potatoes around the filling to seal.

For frying, heat vegetable oil to 350°F (175°C). Drop in stuffed shells and fry until golden, about 3-4 minutes per side, or bake at 400°F (200°C) for 25-30 minutes on a baking sheet.

Once browned, let cool for a few minutes and serve with dipping sauces like ranch or marinara on the side.