Preheat a waffle maker. (Alternatively, you can make these in a nonstick pan using less milk so the mixture is firmer. Use a tiny bit of olive oil to fry them golden brown on both sides)
Peel and cut potatoes into bite-sized chunks so they all cook evenly
Place in a pot with cold water and on high heat to bring them to a boil.
Cook until tender, a fork slides in and out with ease take off the heat and strain out all of the water.
Using a fork mash the potatoes. Season well with salt and pepper. Whisk in the milk, butter, cheddar cheese, and scallions.
Spoon the mixture into a waffle maker and cook until golden brown according to the instructions for using the waffle maker.