Form mashed potatoes evenly into pie crust. Brush lightly with oil. Bake crust at 350 degrees for 30 minutes until lightly browned. When finished, remove crust and turn oven to 375.
While the mashed potato crust is browning, saute vegetables and cook meat. Set aside.
Whisk eggs and half-and-half, adding salt and pepper to preference. Combine cooled vegetables, protein and cheese with egg mixture and pour into prepared mashed potato crust. Bake at 375 for 30-35 until set. Allow to cool 15 minutes or more before serving.