Once the sauce has thickened, whisk the eggs in a separate bowl, add a few tbls of the heated béchamel sauce to the beaten egg, whisking all the time to ensure the eggs don't turn into scrambled eggs. This is known as tempering the eggs and prevents the entire batch of sauce turning into scrambled eggs.
grate in your desired amount of whole nutmeg, I do about 10 scrapes and taste.
Add cheese of your choice for the cheesy option. Check the seasoning and adjust to your liking
Pour into ziplock bags and freeze until ready to use.