Step 1: Add the Chicken - Place the bite size chicken pieces in the bottom of a 6 quart slow cooker and spread them out as evenly as you reasonably can. There is no need to brown the chicken first, which is one of the reasons I like this recipe when the day is already full. Just make sure the pieces are fairly similar in size so they cook at about the same rate.
Step 2: Season the Chicken - Sprinkle the kosher salt, black pepper, garlic powder, onion powder, and poultry seasoning evenly over the chicken. I like seasoning the chicken before adding the rest of the ingredients because it gives those pieces direct contact with all the herbs and spices. Poultry seasoning is especially important here because that familiar blend is a big part of what makes the kitchen smell like chicken pot pie as dinner gets closer.
Step 3: Add the Vegetables and Garlic - Scatter the frozen onion, celery, and carrot mixture over and around the chicken, then add the minced garlic. Pour in the frozen mixed vegetables as well. There is no need to thaw any of the vegetables first. They will have plenty of time to soften while the chicken cooks, and using them straight from the freezer means one less thing for you to remember.
Step 4: Spoon in the Creamy Soups - Spoon the cream of chicken soup and cream of celery soup over the chicken and vegetables. You do not have to make the layer beautiful or perfectly even. Everything will loosen as the broth heats up, and later you will stir the mixture together. Right now, the goal is simply to get that creamy base into the cooker.
Step 5: Add the Broth and Butter - Pour the chicken broth into the slow cooker, letting it work its way around the chicken and vegetables. Cut the unsalted butter into small pieces and scatter those pieces over the top. As the slow cooker warms, the butter melts down into the broth and creamy soups and helps create that rich pot pie style sauce we are after.
Step 6: Slow Cook Until the Chicken Is Tender - Cover the slow cooker and cook on LOW for 5 to 6 hours or on HIGH for 3 to 4 hours. The chicken should be completely cooked through and tender. If you check with a meat thermometer, the chicken should reach 165°F. I usually choose LOW when my schedule allows because I love being able to get dinner started and forget about it for most of the afternoon.
Step 7: Stir in the Heavy Cream - Once the chicken is cooked, pour in the heavy cream and stir everything gently. At this point, the sauce starts looking like the creamy chicken pot pie filling everybody recognizes. Give the bottom and sides of the slow cooker a gentle scrape as you stir so all of the condensed soup mixture becomes incorporated.
Step 8: Add the Potato Gnocchi - Pour the shelf stable potato gnocchi into the slow cooker and stir until most of the gnocchi are submerged in the creamy sauce. Do not add the gnocchi earlier in the day. They cook much faster than the chicken and can become too soft if they sit in the slow cooker for several hours.
Step 9: Make the Cornstarch Slurry - In a small bowl, whisk together the cornstarch and cold water until the mixture is completely smooth. You do not want dry pockets of cornstarch going directly into the hot sauce because they can turn into stubborn little lumps. Mixing it with cold water first takes only a few seconds and gives you a much smoother result.
Step 10: Thicken the Sauce and Cook the Gnocchi - Stir the cornstarch mixture into the slow cooker, cover, and cook on HIGH for another 20 to 30 minutes. Start checking the gnocchi around the 20 minute mark since brands can vary. You are looking for gnocchi that are tender all the way through and a sauce that has thickened enough to coat a spoon.
Step 11: Taste and Serve - Give everything one last gentle stir and taste the sauce before adding any additional salt. Between the broth and condensed soups, you may find that it is already seasoned just right. Spoon the chicken pot pie gnocchi into bowls, scatter fresh parsley over the top if you like, and get it to the table while everything is warm, creamy, and ready for hungry people.