01 - Set your waffle iron to medium-high heat and allow it to fully preheat.
02 - Grate the peeled russet potatoes using a box grater. Transfer the grated potatoes to a clean kitchen towel and firmly squeeze to remove as much liquid as possible.
03 - In a large mixing bowl, combine the squeezed potatoes, grated onion, egg, flour, garlic powder, salt, and black pepper. Mix thoroughly until all ingredients are evenly incorporated.
04 - Pour the melted butter into the potato mixture and stir to combine evenly.
05 - Lightly coat both plates of the preheated waffle iron with vegetable oil or nonstick cooking spray.
06 - Spread an even, generous layer of the potato mixture onto the waffle iron, being careful not to overfill. Close the lid and cook for 10-12 minutes until deeply golden and crispy.
07 - Carefully lift the cooked hashbrowns from the waffle iron using a spatula. Repeat the cooking process with the remaining potato mixture.
08 - Serve the crispy waffle iron hashbrowns immediately while hot, optionally garnished with fresh herbs or accompanied by your preferred breakfast toppings.