Cut the chicken breasts into bite sized pieces and sprinkle with 1 teaspoon of fine grind sea salt and 1 teaspoon of pepper. Set aside.
Finely dice (about ¼-½") 1 celery stalk, 1 carrot, and ½ of an onion.
Slice the mushrooms, cut the remaining 1½ onions into 2" chunks, slice the carrots into ¾" pieces, cut the celery into 1" pieces, and cut the peppers into 1-2" chunks.
Add the butter to the inner pot and turn on sear/sauté on high. When the butter has melted, add in the chicken and spread into 1 layer on the bottom of the pot. Add in the finely diced vegetables, but don't stir. Allow the chicken to cook for about 2-3 minutes to brown and then stir in the finely diced vegetables. Add the flour and stir to combine. Cook another 2 minutes, stirring frequently.
Deglaze the pot with the chicken stock and scrape the bottom of the pot to remove anything that may be stuck on the bottom. Add the remaining seasonings and bay leaves and stir.
Add the larger cut vegetables to the pot and stir. Cut the Yukon gold potatoes into about 1-1½" chunks and add to the stew. Grate the russet potato and add to the pot. You don't have to peel it, but you can if you want to.
Put the pressure lid on and turn the valve to vent. Select the slow cooker function on HIGH for 4 hours.
When the time is up, check the vegetables to make sure they are cooked to your liking. If you want them softer, use sear/sauté on medium and simmer until they are how you like them. Add in the cream, cut up inner leaves of celery and parsley if using. Stir.
See recipe notes½ for instructions on how to thicken the stew if it isn't as thick as you want.
If you want your stew thicker at the end of slow cooking, combine 2 Tbsp of flour with ½-¾ cups of the hot liquid from the stew. Mix really well to remove any clumps of flour and pour into the stew. Use the sear/sauté on high to heat the stew and it will thicken as it heats. If you have stubborn clumps of flour, you can use a fine sieve strainer to strain the flour/liquid mixture before adding back into the stew. You can also use a cornstarch slurry and I would start off with 1 Tbsp of cornstarch mixed in a 2-3 Tbsp of water and add to the stew. Bring the stew up to a low boil to thicken after adding the cornstarch slurry. Nutritional values are provided as a courtesy and thesaltedpepper.com makes no guarantees of accuracy. We do our best to ensure they are accurate, but many factors influence nutritional values that are beyond our control. Different brands of items have different nutritional values, so it is always best to do your own independent nutritional analysis based on the items you are using in a recipe if you require a high level of accuracy. Thesaltedpepper.com will not be held accountable for any errors in the displayed nutritional information.