Combine 1/4 cup mirin, 3 minced garlic cloves, 1 tablespoon freshly grated ginger, and 2 tablespoons sesame oil in a mixing bowl. Pour over 1 pound of sirloin steak in a resealable bag. Let marinate for 30 minutes at room temperature or refrigerate for a few hours.

Heat a large cast-iron skillet over medium-high heat with a splash of oil. Sear the steak for 3-4 minutes on each side for medium-rare. Rest the steak for 5 minutes after cooking.

Add more oil if necessary, then toss in 1 cup of sliced carrots, 1 cup of zucchini, and 1 cup of mushrooms. Sauté for 5-7 minutes until tender.

Add 3 cups of cooked fried rice to the skillet, crumbling it while mixing with the vegetables. Stir for another 3-5 minutes until heated through.

Scoop portions of the rice and vegetables into bowls. Slice the rested steak and lay the pieces on top. Drizzle with yum yum sauce.