Grate the sweet potato and add the minced onion. Lightly salt and mix in the egg. Slowly mix in a little coconut flour at a time. You want to get a consistency that you can easily form a patty that holds. You want <3" patties so they're easier to flip.
Bring coconut oil to heat in a pan. You want enough oil to cover about the bottom half of the potato patties. Fry the patties on each side for ~5 minutes.