Prepare the Potatoes:

Boil and Mash: Boil the potatoes in salted water until tender, about 15-20 minutes. Drain and mash until smooth.

Season and Cool: Stir in the egg, salt, and pepper. Allow the mashed potatoes to cool enough to handle.

Make the Filling:

Cook the Meat: Heat a skillet over medium heat. Add the ground beef or pork and cook until browned.

Add Vegetables: Stir in the onion, bell pepper, and garlic. Cook until softened, about 5 minutes.

Season: Add the tomato sauce, cumin, paprika, cayenne (if using), salt, and pepper. Stir well and simmer for 5 minutes. Stir in raisins and olives, if desired. Remove from heat and let cool slightly.

Assemble the Papas Rellenas:

Form the Shells: Take a handful of the cooled mashed potatoes and flatten it into a disk in your hand. Add a spoonful of the meat filling to the center. Fold the edges over the filling and shape into a ball or oval, fully enclosing the filling. Repeat with remaining potatoes and filling.

Coat and Fry:

Prepare Coating: Set up three bowls for dredging: one with flour, one with beaten eggs, and one with breadcrumbs.

Coat: Roll each stuffed potato ball in flour, dip it into the beaten eggs, and then coat with breadcrumbs.

Fry: Heat vegetable oil in a deep skillet or pot to 350°F (175°C). Fry the potato balls in batches until golden brown, about 3-4 minutes per side. Drain on paper towels.