Source: "So This Is Kosher" by Ann Kaye and Hetty Rance, 1986
Heat the margarine and oil in a large frying pan, and cook the onion and garlic until transparent, stirring constantly.
Mix the matzo meal and the salt and pepper; coat the chicken pieces lightly. Add to the pan in one layer, and cook until browned on both sides. Remove from the pan and keep hot in an ovenproof dish.
Stir in the apples and cook 2-3 min until softened. Pour in the brandy, and ignite it carefully. When the flames die down, add celery leaves and apple juice, and bring to a boil.
Pour the contents over the chicken, cover tightly and bake at 325F for 50-60 minutes until chicken is tender. Transfer the chicken to a serving dish.
Puree the apples and cooking juices (sieve, food mill, food processor). Bring to a rapid boil and reduce to about 1 cup. Add slowly to egg yolks, beating constantly to prevent curdling the yolks. Stir over very low heat until mixture thickens, then pour over chicken. Garnish with watercress and slices of apple (dip apple slices in lemon juice to prevent discoloration).