Preheat oven to 400 degrees.
In a 9 by 13 inch baking pan add the cut potatoes, baby carrots, onions.
Add salt and pepper, HALF of the rosemary and HALF of the olive oil. Using your (clean) hands toss together everything till combined.
Pour in chicken stock.
Cut chicken breasts in half and place on top of vegetables.
Season chicken with a little bit of salt and pepper.
Top the chicken and vegetables with the garlic, remaining rosemary and olive oil.
Bake in a 400 degree oven for 55 - 60 minutes, or until chicken is cooked through and vegetables are tender.