Pre-heat the oven to 400° F. In a medium pot, sauté the chicken in the olive oil until the meat is partially cooked. Make sure that the meat doesn't dry out.
Add the pat of butter, for extra buttery flavor. Add the veggies, corn, peas, bell peppers, onions and celery to the chicken meat. In a separate bowl mix the cornstarch and broth with a wire whisk until the cornstarch is fully dissolved.
Add the broth-cornstarch mixture to the chicken and veggies, then add salt and pepper. Let it simmer. Do not overcook, since this will be baked. While waiting for the mixture to simmer, prepare the pan by lining the bottom with piecrust dough, press the sides gently and makes sure that the bottom crust is centered.
Add the mixture to the pan with the crust dough. Then cover everything with another layer of piecrust dough. Trim the edges if needed so that the seal does not become too thick. Seal the edges of the crust.
Bake in the oven for 30-45 minutes, until the crust is a golden brown.Servings: