2) Whisk in the cream, bring to a simmer, stirring until the mixture thickens and pulls away from the sides of the pan. Pour the sauce into a medium bowl; season with 1 teaspoon of the salt, pepper to taste, and nutmeg. Set aside to cool, stirring occasionally.
3) Stir the poached chicken, parsley, and chives into the cooled sauce. By hand, form the chicken mixture into eight 7-cm long torpedo-shaped croquettes. Put the croquettes on a pan or large plate, cover, and refrigerate for 2 hours or until set and firm.
4) Put a heaping cup of flour in a shallow bowl or lipped plate. In another small bowl whisk the eggs with the remaining salt and pepper to taste. Spread the breadcrumbs into a third shallow bowl.
5) Bread the croquettes. Roll them in the flour, taking care to shake off any excess. Next, dip them in the egg mixture, and finally roll in the breadcrumbs until evenly coated. Place on a plate.
6) Pour enough oil into a large skillet to come about halfway up the sides of the croquettes, and heat over medium heat. Shallow-fry the croquettes until golden brown, about 2 to 3 minutes on each side. Drain on kitchen paper and serve with the mustard.
7) For the poached chicken: Put the parsley, thyme, onion, carrot, celery, and chicken breasts in a medium saucepan. Cover with the broth, and bring just to a boil. Lower the heat to very low and cover.
8) Poach the chicken for 20 minutes or until firm to the touch. Remove the pan from the heat, uncover, cool the chicken in the stock for 30 minutes.
9) Transfer the chicken to a cutting board and reserve the liquid. Bone and skin the chicken and cut the meat into cubes. Discard the bones and skin.
10) Strain the broth and store, covered, in the refrigerator for 3 days or freeze for later use. Remove any fat from the surface of the broth before using.