Prepare the short-grain rice based on the instructions on the package or the rice cooker. Once cooked, transfer to a large bowl.
Add the rice vinegar and sugar, stir together to combine and set aside.
In a large skillet over medium heat, add the cooking oil. Add the chopped mushrooms and cook until slightly shrunk.
Add the spinach and cook until wilted. Set aside.
Add the eggs and cook until scrambled. Set aside.
Once the vinegared rice is at room temperature, add the mushrooms, spinach, eggs and furikake. Gently fold the mixture together until it is well combined.
Stuff the inari age with the rice mixture, about ¼ to ⅓ cup of rice per pouch. Once the pouches are stuffed, enjoy your Inarizushi with a side of soup or vegetables.