Simply spray a muffin pan with olive oil cooking spray ( or wipe down each cup with Olive Oil , crack an egg into the cup, add seasoning ( a dash of hot sauce, salt & pepper, onion powder... ) and a few bits of leftover vegetables. In this case, leftover spinach. If you like, you can use a plastic fork to slightly scramble each egg in the cup.
Pop the tray into an oven set to about 350 degrees for approximately 10-12 minutes, cook, cool completely, then place the egg cups into a freezer bag and freeze until ready to use. I put 3 of the egg cups into a sandwich bag and froze them in groups of 3. This way the night before, I'll be able to pull a single bag out of the freezer, put it in the fridge, and by the time I make it to work the next day...they are thawed.