大学芋 Daigaku imo, literally “the university’s potato”, is a street stall sweet. It’s certainly of Chinese origin, but theses sticky potatoes have become part of the furniture in Japan. Osaka has a famous shop that makes some special ones, dipped in crack maybe, as you can’t stop if you start eaten one. I don’t know their secret. Maybe there is none. You take good satsuma imo (Japanese sweet potato), you fry them and coat in a syrup.
And the results depends on the quality of your ingredients and how you master the process.
Flat and small is easier, so I cut shapes of 5 mm of thickness.
I cook them in 3 steps : steaming till they are half-cooked, then I stir-fry them at 160 degrees C till they soften. I put them aside and bring the oil at 180 degrees, to cook them a little more and get crispiness. I put on oil absorbing paper 2 minutes.
Syrup : 1 tbs of sugar + 1 tbs of honey or mizuame (glucose jelly) + 2 tbs of water. Simmer till it starts getting thicker. Add a few drops of fragrant sesame oil. Pass the freshly fried potatoes (still hot) in this hot syrup.
Decorate with black sesame.
NB : I fry them in normal neutral frying oil, not the dark sesame oil for seasoning. It’s possible to fry in sesame oil but only if you have a different white frying sesame oil.
They have to be soft inside crispy around. They are better if you eat them warm, just after making them.