Prep the flank steak. Thinly slice the steak across the grain; transfer the sliced steak to a large zip-top bag or a large mixing bowl.

Marinate. To the bag, add grated pear, soy sauce, garlic, gochugaru, ginger, brown sugar, and sesame oil. Seal the bag and squish everything around to coat the meat completely with the marinade. Let sit at room temperature for 1 hour, or put in the fridge for up to 8 hours.

Heat the oil. When ready to cook, heat up 1 tablespoon vegetable oil in a grill pan or cast iron skillet set over medium-high heat.

Cook the steak. Remove one-third of the steak slices from the marinade and add them to the hot oil in a single layer; cook for 1 to 2 minutes or until browned.

Continue to cook. Flip over and continue to cook for 2 more minutes, or until browned with crisp edges. Stir occasionally. Cooking time will depend on the thickness of the steak.

Finish. Transfer the cooked pieces to a plate and repeat the above cooking steps with the remaining oil and steak.

Serve. Garnish your beef bulgogi with chopped green onions and sesame seeds, and serve.