In a large bowl, whisk the flour, egg, milk, salt and pepper. Pat potatoes dry; stir into egg mixture. Add onion.
In a large nonstick skillet, heat 2 tablespoons oil over medium heat. Pour batter by 1/4 cupfuls into skillet; cook for 2-3 minutes on each side or until golden brown, adding more oil as needed. Serve with applesauce.