We aren't big fan of leftover mashed potatoes from some reason. I was able to use my left over mashed potatoes and some of the leftover chicken to create a chicken and potato quiche. It was actually better than usual because of using the mashed potatoes (that had butter and garlic in them) verses the plainer potatoes I usually use.
Here's the recipe if you'd like it! If you have roasted chicken, mashed potatoes and veggies anytime soon, just remember it's a great follow up meal! Or to any meal that has mashed potatoes.
Push leftover mashed potatoes into a pie pan. See below.
On top of the potato "crust" put 1 cup cheddar cheese and 1/2 cup onion (and whatever meat you want - I've used ground beef before too and it could easily be meatless as well).
Mix 1 cup of milk, 2 eggs, and salt & pepper (to taste). Pour this mixture on top.
Bake at 400 degrees for about 30 minutes (although last night I must have put more ingredients on because it took about 40 minutes before it was fully golden brown and not "jiggly" on top from the egg mixture.
Add some sides of veggies...