Spray the inside of your crockpot with cooking spray or lightly wipe with oil. Place chicken breasts, chopped onion, vegetables, potatoes, garlic, salt, pepper and chicken broth into crockpot. Cook on low for 8-10 hours or on high for 4-6 hours. Prior to adding the half and half with cornstarch, you will want to remove the chicken breasts, shred them with a fork, and return them to the crockpot to combine with soup.
When it is time, about 30 minutes prior to serving, in a small bowl whisk together the half and half with the cornstarch. Combine this with the soup in the crockpot and give it a good stir. Continue to let it heat, stirring regularly, as it thickens.
You can pre-make the dough for the pie crust, or if available for you, buy a store-bought pre-made pie crust. You will keep the pie crust in the fridge until ready to use. The more cold the crust is, the better and more flaky it will turn out. Follow package instructions if you go this route.
Combine your flour and salt well. Using a pastry blender, take your butter (or substitute) directly out of the fridge and quickly cut it into the flour until you have everything into pea-sized crumbles. Working quickly (everything works best with pie the colder the better), add the water a little at a time, gently and conservatively kneading it together until just moist and just comes together. The less kneading that happens the better, also the least amount of water the better.
Next, separate the dough into two balls. Gently form them into discs. Place them each between two pieces of wax paper. Using a rolling pin, your hands, or even a glass, flatten the discs into 12" circles. You will have two pie crusts. Put them in the fridge on a cookie sheet to keep them flat, and save them for just about 15 minutes before ready to eat.
When you are about 15 minutes out from serving your meal, put your pie crusts into a oven preheated to 350. Bake your crust for 8-10 minutes, or until golden and flaky.
For the vegetables, you can alternately use frozen veggies, and measure out about a total of 1 1/2 cup for the peas & carrots, and 1 1/2 cup for the corn. Play around with this and make it yours. You can really add in whatever veggies you like including green beans etc.
For the crust, we have often times used Pillsbury pre-made store bought crust that already comes rolled out. This has been a friendly option for our peanut allergic child.