Mix all marinade ingredients (except bay leaves) and put in a blender.
Blend marinade mixture on low until lemongrass and garlic are finely chopped. Set aside.
Filter and discard solid particles of the marinade mixture using a sieve.
Combine chicken, marinade mixture and bay leaves in a plastic zip-loc bag, marinate overnight in refrigerator.
The following day, stuff chicken with lemongrass. Let stand for about 30 mins.
Roast chicken in oven at 425°F for 1 1/2 hour (Note: a better way is to use a probe thermometer and when the internal temperature of the thickest part of the chicken reaches 175°, remove the chicken from the oven).
Prepare basting sauce by mixing 2 tbsp. sesame oil to the marinade, baste chicken in oven every 15-20 mins.
Roast until golden brown.
Serve with the prepared gravy (See gravy recipe below).