Place the quartered red potatoes in the bottom of your slow cooker. They'll form a nice base for the stew.
Add the chicken pieces, spreading them evenly over the potatoes.
Pour the condensed cream of chicken soup over the chicken and potatoes.
Add the sliced carrots and chopped celery to the slow cooker.
Crumble the chicken bouillon cubes and sprinkle them over the vegetables.
Season with black pepper, garlic powder, and celery salt.
Cover the slow cooker and cook on High for 5 hours, or on Low for 7-8 hours.
One hour before serving, stir in the frozen peas. They'll maintain their bright green color and won't get mushy.
If using, stir in the heavy cream during the last 30 minutes of cooking for an extra creamy texture.
Stir gently to combine all ingredients before serving.