*Place the chicken breasts on a baking sheet and rub them with olive oil. *Sprinkle generously with salt and pepper. Roast for 35 to 40 minutes, or until cooked through. Set aside until cool enough to handle, then remove the meat from the bones and discard the skin. Cut the chicken into large dice. You will have 4 to 6 cups of cubed chicken.
*In a small saucepan, heat the chicken stock and dissolve the bouillon cubes in the stock. In a large pot or Dutch oven, melt the butter and saute the onions over medium-low heat for 10 to 15 minutes, until translucent. *Add the flour and cook over low heat, stirring constantly, for 2 minutes. *Add the hot chicken stock to the sauce. Simmer over low heat for 1 more minute, stirring, until thick.