Add the pear and onion slices to a blender; process until pureed. If it's dry, add a tablespoon or two of water.
Place the chicken in a large mixing bowl. Add the pureed mixture, green onions, soy sauce, sesame oil, dark brown sugar, rice wine vinegar, ginger, and garlic to the chicken. Stir well to combine. Fold in the carrots and mix everything together.
Cover the bowl with plastic wrap and refrigerate it for at least 2 hours.
Add 2 tablespoons of vegetable oil to a large pan or wok set over medium-high heat. To the heated oil, add half of the chicken pieces without the marinade, and cook for 2 to 3 minutes per side. Remove the cooked chicken from the pan and repeat with the rest of the chicken, adding more oil as needed.
Once all the chicken has been cooked, return all the chicken pieces to the pan and add the leftover marinade. Continue to cook and let the sauce reduce for 3 to 4 minutes.
Remove from heat and serve the chicken bulgogi with your favorite sides.
Notes
Chicken: I used boneless, skinless chicken breasts to make this dak bulgogi, but feel free to use boneless, skinless chicken thighs. You can also substitute the chicken for thinly sliced beef.
Pears: The secret ingredient in bulgogi is pears. They add sweetness and a melty texture to the marinade. So, please don't skip it. D'anjou and bosc pears are both excellent choices.
Marinade: Keep the chicken in the marinade for 2 hours and up to 24 hours.
Make it spicy. Add a tablespoon of Korean gochujang paste to the marinade for some heat.