Combine celery leaves, carrot, green pepper, spinach, chopped parsley, onion and chicken broth in kettle. Tie parsley sprigs, bay leaf, thyme, cloves and garlic in small square of cheesecloth. Add to broth mixture along with rice. Season to taste with salt and pepper. Bring to boil, cover and simmer 40 minutes. Discard seasonings in cheesecloth bag. Press soup through fine sieve or puree in blender. Return soup to kettle and bring to boil. Beat egg yolks and stir a few tablespoons of soup into yolks. Stir yolk mixture into hot soup and cook, stirring, until smooth. Do not boil. Stir in half and half and simmer 2 or 3 minutes, stirring constantly. Remove from heat and chill thoroughly. If soup separates, stir before serving. Spoon into chilled soup bowls. Top each serving with dollop of sour cream and sprinkle with parsley, chives and chopped tomato. (C) 1992 The Los Angeles Times