Spread vegetable oil on a sheet of aluminum foil or a plate.
Deep fry the sweet potato in medium hot oil, until a bamboo skewer can pierce through. Crank up the heat to high and fry for 3 minutes until the skin is crispy.
It's best if the skin is crispy and the potatoes have puffed up a bit.
Put the sugar and water in a small pot or pan over medium heat.
After 6 minutes the sugar will start to color, Cook for a little bit longer to caramelize.
When the sugar has turned dark brown and is starting to smoke, add the fried sweet potato slices and toss rapidly to coat.
Coat the sweet potatoes well.
Line up the sweet potato pieces on an oiled foil or plate, so that the pieces aren't touching each other.
Let rest for a while (10 minutes or so) and the candy coating will become brittle and hard.
I made hard candies with the remaining caramel.
Story Behind this Recipe
I thought that daigaku-imo would be delicious with a caramelized coating, and it was better than I imagined. ☆
If you heat sugar with water, the sugar will melt and become liquid in 3 minutes, and it'll crystallize in 5 minutes. But if you wait longer, the sugar will start to cook and turn color in 6 minutes. The crunchy sugar coating melts by the next day, so eat this as soon as possible!