Cut chicken into pieces. Place chicken in a deep saucepan; cover with cold water. Add salt, leek, celery, carrot, whole clove, bay leaf and onion. Bring to boil; reduce heat. Simmer 1 to 2 hours, depending on size and tenderness of chicken. When joints linking thigh portions to main body move easily and seem flexable, chicken will be done. Remove chicken from cooking liquid; cool slightly. Remove skin and fat; cut flesh from bones in large pieces. Strain liquid. Cut mushrooms into thin slices. Sautee in a small amount of butter in a medium skillet. Melt butter in a large skillet. Stir in flour. Cook, stirring constantly, until light golden brown, about 3 minutes. Add a small amount of hot cooking liquid and season with salt, nutmeg, Worcestershire sauce, wine and lemon juice. Place chicken pieces, sauteed mushrooms and peas in sauce; warm gently over low heat. When all ingredients are hot, turn off heat. Let stand 3 to 4 minutes. Before serving, blend egg yolk and whipping cream in a small bowl. Stir egg yolk mixture into sauce to make it smooth and rich. Serve hot with rice.