In the crockpot, place the boneless, skinless chicken pieces, chopped onion, diced bell peppers, sliced mushrooms, and minced garlic.
Slice the butter into small pieces and spread them over the chicken.
In a separate bowl, combine the soup, chicken broth, heavy cream, dried thyme, dried parsley, salt, and pepper. Mix well.
Pour the chicken broth and cream mixture over all the other ingredients in the crockpot and mix well.
Cover the crockpot and cook on low for 4-5 hours or high for 2-3 hours, or until the chicken is cooked through and tender, and the flavors have melded together. Stir halfway through if able.
About 30 minutes before serving, add the frozen peas, frozen carrots, and diced pimientos to the crockpot. Stir them into the mixture.
Continue cooking on low for the remaining 30 minutes.
Before serving, taste the Chicken à la King and adjust the seasoning with more salt and pepper, if needed.
Serve your Chicken à la King over cooked pasta, biscuits, or rice depending on your preference. Enjoy!