Start by heating your oven to 400.
Fry the bacon in a skillet using medium heat, and then drain the oil, placing it to the side.
Grease your muffin tin with the bacon grease, lining each one with a slice of bacon.
Beat your eggs in a bowl.
Add your spinach to the egg mixture, and then divide it between your muffin tins.
Sprinkle with cheese and season, baking for another fifteen minutes.