Preheat the oven to 350 degrees F. Distribute 12 foil muffin holders into a muffin baking pan. It is best to use foil papers here.
Cut the sandwich bread into half inch squares and evenly distribute them on the bottom of the muffin cups
In a mixing bowl or large measuring cup that has a pour spout thoroughly whisk together the eggs and milk. Add a few dashes of salt and pepper if desired.
Evenly distribute the egg mixture into each muffin cup. It’s okay if the bread pieces float to the top. Add a few spinach leaves (you may need to shred a bit)
Sprinkle an equal amount of both the grated cheese and the crumbled bacon (or sausage) into each muffin cup on top of the egg mixture.
Bake at 350 for 15 minutes or until eggs are set. Enjoy or freeze (in-between sheets of wax paper) for another day!