Prepare potatoes by mixing leftover mashed potatoes until smooth or boil, peel, and mash fresh potatoes.

Mix mashed potatoes with flour, egg, salt, and pepper until fully combined and thick enough to form fries.

Shape the mixture into uniform fry shapes about ½ inch thick and arrange them on parchment paper.

Heat oil in a deep fryer to 350°F (175°C) and fry the formed fries for 3-4 minutes until golden brown, flipping halfway.

Allow fries to cool slightly before serving with various dipping sauces.