In a large plastic bag or a bowl, combine flour, oregano, pepper and salt. Shake or stir in chicken pieces to coat. In a heavy pot, melt 3 tablespoons of the butter and stir in all the chicken and flour at once. Stir often until chicken and flour are lightly browned, about 2-3 minutes. Set chicken aside. Add remaining butter to pan and saute vegetables for about a minute. Stir in chicken and cook until onions are softened. Then add chicken stock and rice. Bring to a boil. Cover and cook over medium-low heat for 20 minutes. Remove from heat and stir in cream. Serve with lots of fresh, hot, buttered bread.