Heat butter and olive oil on medium high heat in a large, thick-bottomed pot.
Add the onions, celery, and carrots. Cook for 5 minutes until just starting to soften. Add the bay leaves. Add the curry powder and mix to coat.
Add the chicken thighs and stir to coat with the curry mixture. Add the stock and water to the pot. Add the salt. Bring to a simmer and reduce the heat to maintain a simmer. Cover and cook for 20 minutes.
Remove the chicken pieces from the pot. Place on a cutting board and allow to cool to the touch.
Add the rice and the chopped apples to the soup. Simmer on high heat, then lower the heat to maintain a low simmer. Cover and cook for 15 minutes, until the rice is cooked through.
Meanwhile, shred the chicken and discard any tough bits. Once the rice and apples in the soup are cooked, add the chicken back to the pot. Heat for 5 minutes more. Then stir in the cream.