Steak Bento Box Recipe

Make marinade

In a shallow bowl or resealable bag combine soy sauce (3 tbs), mirin (2 tbs), sesame oil (1 tsp), brown sugar (1 tbs), minced garlic (2 cloves), grated ginger (1 tsp), 0.5 tsp salt and 0.25 tsp black pepper. Stir until sugar dissolves.

Marinate steak

Trim the steak of excess fat and pat dry. Place steak in the marinade, ensuring it is coated. Marinate refrigerated for 30 minutes to 2 hours (30 minutes for quick service, up to 2 hours for deeper flavor).

Cook steak

Remove steak from refrigerator 15 minutes before cooking to come toward room temperature. Heat a grill or heavy skillet over medium-high heat and brush with 1 tsp vegetable oil. Remove steak from marinade, shake off excess, and sear 3-4 minutes per side for medium-rare (thicker cuts may need longer). Internal temp: 130-135°F (54-57°C) for medium-rare. Adjust time for desired doneness. Transfer to a cutting board and rest 8-10 minutes.

Slice steak

Slice the rested steak thinly against the grain into bite-sized strips for the bento box. Reserve any juices to drizzle over rice or steak.

Rinse 1 cup short-grain rice under cold water until the water runs mostly clear to remove surface starch. Drain.

Combine rinsed rice and 1.1 cups water in a small saucepan. Let soak 15 minutes if time allows. Bring to a gentle boil over medium-high heat, then reduce to low, cover tightly, and simmer 12-15 minutes until water is absorbed. Remove from heat and let rest, covered, 10 minutes.

Fluff rice with a fork, stir in 1 tsp rice vinegar and 1/8 tsp salt. Keep warm until assembly.

Thinly slice 1/2 cucumber into rounds or half-moons. Place in a small bowl.

Whisk together 2 tbs rice vinegar, 1 tsp sugar, 1/4 tsp salt and 1/8 tsp red pepper flakes (if using) until sugar dissolves.

Pour dressing over cucumber slices, toss to coat, and let sit at least 10 minutes. For best results chill 30 minutes. Drain lightly before packing into bento compartment.

Heat 1 tsp vegetable oil in a skillet over medium-high heat. Add 0.75 cup sliced shiitake mushrooms and sauté 2-3 minutes until beginning to soften.

Add 2 cups baby spinach (or chopped bok choy) and continue to sauté until wilted, about 1-2 minutes for spinach or 3-4 minutes for bok choy stems.

Toss with 1 tbs mirin, 1 tsp soy sauce and 1 tsp sesame oil. Cook 30 seconds more to reduce the liquid slightly. Remove from heat and sprinkle 0.5 tsp sesame seeds over the vegetables.

Divide the fluffy rice evenly among bento compartments or containers.

Arrange sliced steak over or beside the rice. Drizzle any reserved steak juices or a little extra soy-mirin mixture over the steak and rice if desired.

Add a portion of the sautéed vegetables and pickled cucumber to separate compartments so flavors remain distinct.

Garnish with sliced scallions, pickled ginger (if using), toasted sesame seeds, and a lemon wedge or a small container of chili mayo/sriracha for dipping.

If packing to-go, let hot items cool slightly before closing the bento box to avoid condensation. Store refrigerated and consume within 24 hours; reheat steak and rice gently if desired.