Finely dice the bacon and onion (if using). Cook in a large frying pan until the bacon is crispy
Peel and grate the potatoes, add to a fine mesh bag or large muslin cloth, squeeze out as much liquid from the potatoes as possible, add to a large bowl
Grate the cheese and add to the bowl
Add the cooked bacon and onion to the bowl
Whisk an egg and add to the bowl, season with pepper
Mix well until all of the mixture is coated in the egg
Spoon small amounts into a waffle maker and cook each individual waffle until golden brown and crispy
Serve - if packing into a childs lunchbox, allow to completely cool or leave in the fridge overnight