In a large pot or Dutch oven, melt the butter and saute the onions over medium-low heat until translucent, about 10 minutes. 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 and stir for another minute, until the sauce becomes thick. Add 2 teaspoons salt, 1/2 teaspoon pepper, and the heavy cream. Add the cubed chicken, carrots, peas, onions and parsley and mix well.