Soak the soybeans. Fill a bowl with water and gently add the soybeans, stirring twice. Cover with lid and let it sit in room temperature overnight.
The skins of the soybeans will also expand without breaking. Transfer the beans with the soaking water to a pot and boil on medium heat. Once it boils, reduce the heat to low and simmer for 15-20 minutes, until slightly tender. While simmering the beans, soak the hijiki seaweed in water until softened.
Scrub the carrot and cut into 1 cm cubes. Cut the shiitake mushrooms including the stalk (chop off the tough ends) into 1 cm cubes, pour hot water over the aburaage and cut into thirds. Separate the layers of the aburaage and julienne.
Stir-fry the carrot, shiitake mushrooms and aburaage in sesame oil. When thoroughly incorporated, add the well-drained hijiki and stir-fry.
Next, add the drained soy beans and briskly toss the ingredients. Add sake, sugar, dashi, and water. Bring to a boil, then cover and simmer on low heat for about 10 minutes.
Remove the lid and drizzle in the soy sauce and mirin. Cover again and simmer for about 10 more minutes.
Remove the lid, raise the heat, and stir with chopsticks until the liquid has evaporated enough to your liking.
Story Behind this Recipe
I attempted to recreate the flavor of my mother's hijiki soybean simmer. Instead of vegetable oil, I used sesame oil for stir frying for a touch.
You can use pre-boiled soybeans, but note that the beans will slightly crumble. I used fresh shiitake but dried shiitake adds more flavor to the dish. Substitute the soaking liquid from the shiitake mushrooms for part of the water for a boost of umami. For other vegetables, try lotus root or konyaku. You can also freeze the leftovers, by separating into individual servings.