Chop up your cooked bacon, vegetables and crumble/grate the cheese.
Add half of your fillings to the greased muffin tin.
Divide the egg mixture between the muffin holes.
Add the rest of the fillings, making sure the mixture doesn't go higher than 3/4 of the holes.
Put in a preheated oven at 200C for 20 minutes, until the egg is cooked through and risen.
Make sure you have really greased your muffin tin before pouring the mixture in, as they can easily stick and you will end up leaving half the muffin in the tin when trying to get them out. Using a good non stick muffin tin helps too. If you don't want to use oil to grease the muff tin, then you could always use silicone cupcake moulds in the muffin turn and they will easily come out of those.
Leave them to cool for about 10 minutes before getting them out of the tin, and run a knife around the muffins to loosen them.
These egg muffins do puff up whilst cooking, so you don't want to pour the mixture all the way to the top of your tin. Just pour to about 3/4 full and they will rise when cooking.
You can easily double or triple this recipe if you are feeding a crowd, or just want to make extra to keep in the freezer for easy weekday breakfasts.
If you are using spinach, I would recommend cooking it and squeezing out the excess water first. If you add raw spinach to these, the muffin itself might get quite liquidy.
Want to make these lower in calories? Apart from swapping the fillings to less cheese and more veggie base, you can use 4 egg whites and 2 whole eggs, rather than 4 whole eggs that we have used in this recipe.