If rice cake is hardened, soak in cold water until softened.

Season rice cake with 1 tbsp sesame oil and 1 tsp soy sauce.

Julienne onion, carrot, and bell pepper.

In a bowl, mix sesame oil, soy sauce, minced garlic, rice wine, chopped green onion, brown sugar, and a pinch of pepper to make the marinade.

Marinate sliced mushrooms and julienned beef in the marinade for 10 minutes.

Heat oil in a pan over medium heat.

Stir-fry the vegetables quickly and gather them on one side of the pan.

Add the marinated beef and mushrooms to the pan.

Stir-fry the beef and mushrooms with the vegetables until cooked.

Lower the heat and add the seasoned rice cake.

Add soy sauce, sesame oil, brown sugar, and pepper to the pan.

Stir-fry until the rice cake is cooked through and the sauce has thickened.