Preheat oven to bake at 180°C. Spray a 12 cup non-stick muffin tin with cooking spray.
Add oil to a large non-stick skillet/frying pan over medium-high heat and sauté bacon until almost done (2-3 minutes). Use a wooden spoon to stir bacon in a pan.
Add diced onion to bacon, turn down heat to low and cook until onion is translucent. Remove from heat. Remember to switch off the stove.
Spoon the bacon and onion into the muffin cups, using a tablespoon.
In a large measuring jug, crack the eggs, add salt and mixed herbs and whisk using a balloon whisk.
Pour egg mixture into the muffin cups over the bacon and onion, filling cups ½ to ¾ full.
Sprinkle grated cheese over the egg mixture.
Bake for 15 minutes until puffy and golden brown. Remember to use oven gloves to take tin out of the oven and remember to switch off the oven.
Cool for 5 minutes in the muffin tin, transfer to cooling rack and serve while still warm.
Storage instructions for fridge or freezer and how to re-heat egg muffins
First, let the muffins first cool completely on a cooling rack.
Fridge storage: Place completely cooled muffins in an airtight container and refrigerate for up to 5 days.
Freezer storage: Place completely cooled muffins in a freezer bag, try to get out as much air as possible and freeze for up to 3 months.
Reheat: When you’re ready to enjoy muffins from the fridge, microwave uncovered in 20-second increments, until hot. To reheat from the freezer, microwave uncovered in 30-second increments until hot.