Spray a baking dish large enough to hold the chicken and vegetables with non-stick vegetable spray.
In a small bowl, combine the parsley, sage, rosemary and thyme, and a generous amount of pepper.
Quarter the potatoes (do not peel), then cut them into 1/2" pieces.
Rub some salt and about 2 tsp.
of the herb mixture mixture into the cavity of the chicken.
Then place one of the bay leaves into the cavity and tie the legs together so the chicken will hold its shape.
Rub some salt on the outside of the chicken and brush with some of the olive oil.
Sprinkle half of the remaining herb mixture all over the chicken and place in the baking dish.
In a large bowl, toss the potatoes and shallots with the remaining olive oil and herb mixture, and the remaining bay leaf, crumbled into a few pieces.
Spoon the vegetables evenly around the chicken in the baking dish and bake, uncovered, for about 1 hour and 15 minutes, or until the juices run clear when pierced in the thickest part of the thigh and the legs can be moved easily.
While baking, occasionally baste the chicken and turn the vegetables.
When the chicken is done, remove the chicken and vegetables from the baking pan and arrange on a platter.
Cover with a tent of aluminum foil or a large domed pot cover to keep warm while you prepare the sauce.
(If necessary, you can keep it warm in a very low oven.) SAUCE: Pour the pan juices into a large glass measuring cup and degrease.
(One way is to dab the grease that has risen to the top with clean, dry paper towels until it is soaked up.) Add enough stock to measure 2 cups.
Pour the balsamic vinegar into the baking pan and bring to a boil over medium heat on top of the stove, scraping up any browned bits.
(You can continue working in the baking pan or transfer the contents of the baking pan to a small saucepan at this point-- whichever is easiest for you).
Boil for about 4 minutes or until reduced to a glaze.
Add the stock mixture and continue boiling until liquid is reduced to about 1/2 cup.
This should take about 10 minutes.
Reduce the heat to low and whisk in the butter, one piece at a time, until it is all incorporated.
Taste the sauce and adjust the seasonings to taste.