01 - Bring a large pot of salted water to a boil. Add the potatoes and cook for 15-18 minutes, or until fork-tender.
02 - Drain the potatoes well. Return to the pot and mash until smooth.
03 - Stir in the butter and milk until fully incorporated. Season with garlic powder, onion powder, smoked paprika, salt, and pepper. Let the mash cool for 10 minutes.
04 - Add the egg to the cooled mashed potatoes and mix thoroughly.
05 - Transfer the mixture to a piping bag fitted with a large star tip, or shape by hand into fry-like sticks.
06 - For baking: Preheat oven to 425°F. Line a baking sheet with parchment paper. Pipe or arrange the mashed potato sticks onto the sheet. Lightly brush with oil. Bake for 20-25 minutes, turning halfway, until golden and crisp. For frying: Heat vegetable oil in a deep pot to 350°F. Carefully lower the shaped potato fries in batches. Fry for 2-3 minutes or until golden and crispy. Drain on paper towels.
07 - Serve hot, garnished with parsley or Parmesan if desired.