Melt butter in large pot. Saute onion, carrots and celery until lightly brown. Remove from heat and stir in flour and curry powder until well blended. Return to heat and cook for 3 minutes, stirring constantly.
Add chicken stock and simmer, covered, for 30 minutes. Add the apple, rice, chicken, salt, pepper and thyme and simmer for 14 minutes longer. Add hot cream. Blend well and serve.