Marinaded koji flank steak grilled to perfection then paired with crispy, crunchy rice all drenched in salty miso butter.
This dish is a veritable umami bomb. Umami has been identified as the fifth taste, along with sweet, salty, sour and bitter. Between the koji, miso and seaweed flakes in the furikake it’s a veritable glutamate-fest.
Although koji is an ingredient created by an ancient Japanese process, it’s relatively new in terms of being commonly used and adored by western chefs. It takes the place of salt as a seasoning and is actually a form of mold. You can read all about it here. One of the benefits of koji is that it acts as a tenderizer in addition to bringing a distinct flavor, which makes it a perfect steak marinade.

If you’ve ever enjoyed a bowl of Korean bibimbap, you may be a fan of the crispy rice that forms as the rice sits against the searing hot stone bowls. Heck as far as I’m concerned, that dish is all about that crispy rice, and there never seems to be a enough of it. Solution? Make you own in a skillet, and transform the entire batch into guaranteed golden crispy goodness.
Liking the sound of the recipe but worried about all the extra ingredients? Fear not! You can definitely make this without the koji marinade, just season liberally with salt before you grill the steak and skip the marinade step.

Koji Flank Steak with Crispy Rice & Miso Butter
- Yield: serves 4-6 1x
Ingredients
1.5–2 lb flank steak
4–5 tablespoons Koji (ground)
4 cups cooked sushi rice
1/2 cup vegetable oil
4 teaspoons cream or milk
1 tablespoon Furikake rice seasoning
2oz butter, at room temperature
2 tablespoons miso paste
2 green onions/scallions, finely chopped
salt to taste
Instructions
- Pat the flank steak dry on both sides using paper towel. Spoon the shio koji over the surface, covering well, then place into a ziptop bag and seal. Place the bag into the refrigerator to marinate for 4-6 hours or overnight.
- Spread the sushi rice out on a tray lined with parchment paper to allow the grains to dry out as much as possible. Ideally, it will sit for at least 30 minutes to dry.
- Pre-heat a grill to high heat, about 20-30 minutes before you’re ready to cook the steak.
- To prepare the crispy rice, you will work in batches. Add half the oil and half the cream to a nonstick skillet over medium high heat. Whisk to combine. When hot, add half the rice, pressing down gently with a large spoon to form a large flat disc that covers the entire base of the pan. Season with salt. Lower the heat to medium and cook 10-15 minutes until the grains begin to color and become crisp on the bottom. Remove to a large bowl and repeat with the remaining oil, cream and rice.
- Add the Furikake to the bowl and toss to combine with the crispy rice.
- Combine butter and miso paste in a small bowl, and mix well with a spatula to combine, then set aside.
- Scrape the excess koji from the steak then place onto the oiled grill. Cook the steak, turning every 3 minutes, until a nice color has developed and it reaches an internal temperature of 130-135 degrees on a meat thermometer. Remove steak to a board and cover with foil, allow to rest 10 minutes.
- To serve – spoon crispy rice into the bottom of a shallow bowl. Slice steak (after resting) and nestle several slices on top of rice. Top with a generous amount of miso butter and a sprinkle of chopped scallions.
Great meal. We coupled it with miso soup.