In a medium bowl, mix the ground pork, shallot, mushrooms, sugar, fish sauce, soy sauce, salt, pepper, and chinese 5 spice.
Heat a large skillet under medium high heat and add 1 tablespoon olive oil. Cook pork mixture until browned and broken up. Turn off heat and set aside to cool.
Once the pork mixture is cooled, mix in with mashed potatoes. Season with salt and pepper, if needed.
Shape the mixture into small to medium sized balls, about 1 to 1 & 1/2 inch in diameter should be fine. Dip each ball into the flour, shaking off any excess. Then dip in eggs, and roll in panko.
Heat a large dutch oven under medium high heat and fill with about 3 inches of oil. When temperature is about 350 F, start heating balls in batches, about 5 balls per batch should do it. Fry until golden brown, about 3 minutes or so, and drain on paper towels.