Preheat oven to 350 degrees.
Spray a loaf pan with non-stick cooking spray and set aside.
Layer the first four ingredients in the order listed, pressing each layer firmly.
Add 1 cup of turkey gravy over ingredients in the loaf pan.
Top with mashed potatoes. I use a pastry bag with a large tip and decoratively piped the potatoes, but you can spread them over the top.
Sprinkle the top of the potatoes with the crispy onions.
Bake in preheated oven for 45 minutes to 1 hour until heated through and the potatoes are golden brown.
Remove from oven and allow to set for 10 minutes.
Heat remaining 1 cup of turkey gravy.
To serve sliced loaf and pass the remaining gravy.