Blend first 10 ingredients together in large bowl. Once blended, spoon into 7 x 11" casserole dish, or an 8x8" square casserole dish, mounding up mixture in the middle of the casserole.
Drape pie crust over casserole dish and crimp edges to seal.
If baking immediately: preheat oven to 400 degrees. Brush crust with beaten egg. Place place of aluminum foil loosely over crust to prevent over-browning. Place on cookie sheet and bake 40-45 minutes. Allow to sit for 10 minutes before serving.
If freezing: place unbaked pot pie on cookie sheet, uncovered. Freeze overnight. Wrap securely in plastic freezer wrap or in a freezer-safe container and store in freezer. To bake, do not thaw. Preheat oven to 400 degrees. Brush crust with beaten egg. Cover crust loosely with piece of aluminum foil. Place on cookie sheet in oven and bake for 1 1/4 to 1 1/2 hours, or until browned and bubbly. Allow to sit for 10 minutes before serving.