In a bowl, combine the soy sauce, brown sugar, sesame oil, minced garlic, black pepper, and chopped green onion. Add the sliced beef, ensuring it’s well coated. Let it marinate for at least 15 minutes.

Heat a grill pan or skillet over medium-high heat. Add the marinated beef and cook until it’s browned and cooked through, around 5-7 minutes. Remove from heat and let it cool slightly.

Once the sushi rice is cooked, allow it to cool slightly, so it’s easier to handle.

Place a sheet of nori on a bamboo sushi mat. Wet your hands to prevent sticking, then spread a thin layer of sushi rice over the nori, leaving about 1 inch at the top edge.

Lay a few pieces of cooked bulgogi, cucumber, and avocado on top of the rice.

Starting from the bottom, roll the sushi away from you, applying gentle pressure. Use the mat to help shape and tighten the roll. Dip your finger in water and moisten the top edge of the nori to seal the roll.

Using a sharp knife, slice the roll into bite-sized pieces. Serve with soy sauce, pickled ger, and optional spicy mayo on the side. Enjoy!