Grate cauliflower on a box grater until shredded. Transfer to a medium bowl and add egg, onion, cheddar and cornstarch. Season with salt and pepper.
In a large skillet over medium-high heat, heat oil. Add spoonfuls of cauliflower mixture and shape into a patty. Cook until brown and crispy, 5 minutes, then flip and cook 5 minutes more. Repeat with remaining cauliflower mixture.
Recipe by Slim Pickins at https://www.slimpickins.org/2018/09/01/cauliflower-hashbrowns/