Heat a large Dutch oven (or heavy-bottomed soup pot) over medium-high heat. Add the oil and brown the thighs on both sides, about 3 minutes per side. Add the garlic, rosemary and tomato paste. Stir the tomato paste to allow it to caramelize a bit, and allow the garlic and rosemary to become slightly aromatic, about 1 minute.
Deglaze the pan with the vinegar. Add the stock and brown sugar. Bring liquid to the boil then reduce to a simmer. Stir in the olives. Simmer the stew, covered, for 1 hour.*
Remove the cover and continue to cook another 15 minutes to concentrate the sauce. Stews are always better the longer they cook, so if you have more time, by all means cook it longer. You may need to add more stock or water. Taste and adjust seasoning with salt and pepper. Garnish with parsley, if desired.
While the chicken is simmering, bring a large pot of salted water to the boil. Cook the egg noodles according to package directions. Drain and reserve.
Divide the egg noodles between 8 bowls. Top with chicken and sauce.
*optional oven method: instead of simmering on the stovetop, move the stew to a 325ºF. oven and continue as directed.