Lightly grease an 8 x 8 pan or 2 quart baking dish with cooking spray.
Spread half of the steak fries in the bottom of the baking dish.
Layer half of the feta, bacon, spinach and onion.
Top with the remaining steak fries.
Sprinkle with the rest of the onion and spinach.
In a medium sized bowl, whisk together eggs, milk, pepper, salt and garlic powder. Pour over the breakfast casserole.
Top with feta and bacon, then refrigerate overnight.
In the morning, bake at 350 degrees for 60-70 minutes or until eggs are cooked. Enjoy!