Preheat oven to 350 degrees. Spray 9 inch pie plate with cooking spray. Roll out pie crust and put in pie plate.
In a medium bowl, beat the eggs, milk, and salt until well combined. Fold in the ham and Cheddar cheese. Break off pieces of the cream cheese and add that in as well. Fold everything together gently to combine.
Pour egg mixture into pie plate. Bake for 45-55 minutes until the crust is a golden brown and the eggs are set.
Let stand for 5 minutes and cut into 8 wedges. Garnish with green onion, optional.