If the sweet potato skin is clean, just remove any dirt and slice the sweet potato into 1/4-inch (about 7 mm) thick rounds. Soak the slices in water for about 15 minutes, then drain well.

In a bowl, mix the flour and salt. Add the water and egg, and mix until combined. Dip the sweet potato slices into the batter to coat them.

Fry the sweet potato slices for 1 1/2 minutes on the first side. Flip and fry for about 1 more minute.

Check doneness by inserting a skewer or toothpick to make sure the sweet potatoes are cooked through.