In a mixing bowl, whisk together soy sauce, brown sugar, sesame oil, minced garlic, and ginger until well combined. Coat the steak evenly with the marinade and let it marinate for 15–30 minutes.

While the steak marinates, prepare your rice according to package instructions for fluffy rice, using a ratio of 1 cup rice to 1.5 cups water. Cook for about 15–18 minutes, then fluff with a fork.

Heat a grill pan over medium-high heat until hot, then place the marinated steak onto the pan. Sear the steak for about 4–5 minutes on each side for medium-rare. Let it rest for 5 minutes before slicing.

In a small bowl, combine mayonnaise, Sriracha, and lime juice. Mix until smooth, adjusting Sriracha based on your spice preference.

In each bowl, spoon fluffy rice, layer on sliced steak, drizzle with the spicy cream sauce, and finish with chopped green onions.