Cut the peeled potatoes into quarters and put them into a pot. Cover them with 1 inch of water then bring the pot to a boil. Continue to boil until the potatoes are soft, about 12-15 minutes. Drain the water then put the potatoes back into the pot.
Add the butter and salt to the potatoes and mash them well with a potato masher. Put them into your fridge, uncovered, and let cool.
When the potatoes are cold, add the crispy bacon, cheddar cheese, chives, and egg to the mashed potatoes and mix well.
In a wide bowl, whisk the remaining eggs with 2 tablespoons of water. Add the panko to another wide bowl.
Use a medium-sized cookie scoop to scoop out 28 balls. Dip the balls first into the egg and then into the panko. Move all the rolled balls to a cookie sheet or a plate.
Heat the oil in a high-sided frying pan. Working in 2-3 batches, fry the mashed potato balls just until they turn golden.
This is a great recipe to use leftover mashed potatoes, like these Roasted Garlic Mashed Potatoes. You'll need about 3 cups of leftover mashed potatoes to make this recipe.