Yusuke says that this dish, daigaku-imo, is always a favourite among Japanese children for their school lunch. And it’s no wonder: it’s mondo-sugary.
A web search in English retrieves lots of pictures and recipes. Yusuke’s Japanese searching found a few origins for the name, which can be translated as “university potatoes.” Apparently the dish originated as a treat prepared and sold by university students for a little extra cash in Tokyo in the 1940s. Another story says that daigaku-imo was first created at a sweets shop near Tokyo University and became a huge fad before the Pacific war.
Yusuke made a little Canadian variation. We can’t usually find Japanese sweet potatoes here, which are purple in colour, so we went with the familiar (to me) orange ones. He cubed the potato and soaked in salty water for a while. Then he fried it in a canola oil in a frying pan since we don’t have a deep fryer.
Meanwhile, he made the sauce with:
6 (!) tbsp of maple syrup
splash or two of mirin
splash or two of soy sauce
1 1/2 tbsp water
He simmered the sauce until thick and sticky and then added the potatoes, mixing well.
Sprinkled with sesame seeds to serve.
Most recipes call for white or brown sugar (or both) or sugar syrup, but Yusuke opted for maple syrup instead, to great success.
And for a random aside, I just discovered that Kit Kat bars come in a bizarrely diverse range of flavours in Japan, including, among many others, chestnut, watermelon and salt, cherry blossom, apple vinegar, kinako, and…daigaku-imo. Wikipedia has a list of the various flavours, and I also enjoyed some reviews of the candy here and here.