Combine the flour and baking powder in a bowl and mix until combined.
In a separate bowl, whisk the egg.
Add the mashed potatoes and shredded cheese to the bowl with the egg and mix until it is well combined.
Add in the flour and mix until it is just combined and incorporated.
Spray your waffle iron if needed. Scoop a small amount of the mixture into a preheated waffle iron and cook according to your waffle maker’s instructions.
