Boil aburaage: Bring a pot of water to a boil. Add aburaage and boil for 1 minute on each side, pressing them down into the water. Drain and rinse the aburaage. Gently press down on them to remove excess water (they tear easily so be careful).
Roll and cut aburaage: Place aburaage on a cutting board. Use a chopstick to roll out each aburaage. This helps separate the layers, making them easier to open and stuff later. Cut aburaage in half so you have 12 square pieces.
Add to saucepan with seasonings: Mix sugar, soy sauce, mirin, water, and dashi powder in a saucepan. Add aburaage pieces on top overlapping. Place an otoshibuta (drop lid) on the aburaage (see notes if you don't have otoshibuta**2).
Simmer: Turn heat on medium low and simmer the aburaage until most of the liquid is gone (about 10 minutes). You can flip the aburaage halfway for more even seasoning, but it's not completely necessary.
Cool: Remove from heat when there is still a little bit of liquid left in the pan. Set aside to cool uncovered.
Store: Transfer inari age and any remaining cooking liquid to an airtight container. Store in the fridge for up to 3 days. To freeze, drain excess liquid then wrap individually or layer with foil or parchment paper so they don't stick. They will last in the freezer for up to a month.
Notes
This recipe makes lightly seasoned inari age. Still very flavorful, but if you prefer the sweeter store-bought versions, use 3 tbsp each of sugar, mirin, and soy sauce.1) Kombu Dashi: Use 1/2 teaspoon kombu dashi granules* + 200ml water, or make kombu dashi by soaking 3 grams of dried kombu in 200ml water overnight in the fridge or at room temperature for 2-3 hours.2) Otoshibuta: You can make a makeshift otoshibuta with parchment paper or foil. Cut or fold it to a shape just slightly smaller than your pan's circumference so it can sit on top of the food. Poke a few holes in the paper/foil to let steam escape.