Cut the beef into easy-to-eat pieces. Slice the onion into thin wedges. Chop the leek finely.
Mix together 1 tablespoon of mirin, 1/2 of grated garlic, the finely chopped leek and 1 teaspoon of the shio-koji to make the sauce.
Marinate the beef in the sauce for a while so that the flavors penetrate it.
Heat 1 teaspoon of sesame oil in a frying pan, and stir-fry the onion until translucent.
Spread the beef slices out in the pan and stir-fry.
When the meat is cooked, add 1 teaspoon of shio-koji, stir fry quickly and it's done.
Portion out the rice in your bowl, top the rice with cooked beef, and garnish as desired with shredded shiso leaf.
Story Behind this Recipe
When I was chosen to be a recipe tester for a certain brand of shio-koji, I used the shio-koji to make this easy and umami-rich 'Salted Beef Bowl'.
The saltiness will differ depending on the shio-koji you have, so please adjust accordingly. It has a slightly salty flavor because of the mirin, but it goes well with rice. This burns easily, so high heat is prohibited.